state pattern (vending machine example)

DesignPattern/ChainOfResponsibility/AddHandler.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal class AddHandler : CalcHandler
+    {
+        public override int Calculate(CalcType cType, int a, int b)
+        {
+            if (cType == CalcType.Add)
+                return a + b;
+            else
+                return Next.Calculate(cType, a, b);
+        }
+    }
+}

DesignPattern/ChainOfResponsibility/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8.1" />
+    </startup>
+</configuration>

DesignPattern/ChainOfResponsibility/CalcHandler.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal abstract class CalcHandler
+    {
+        public CalcHandler Next { get; set; }
+        public abstract int Calculate(CalcType cType, int a, int b);
+    }
+}

DesignPattern/ChainOfResponsibility/CalcType.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal enum CalcType
+    {
+        Add,
+        Subtract,
+        Multiply,
+        Divide,
+    }
+}

DesignPattern/ChainOfResponsibility/ChainOfResponsibility.csproj

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{808A59EA-EF38-4D24-B4C9-ADD93D21EDDC}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>ChainOfResponsibility</RootNamespace>
+    <AssemblyName>ChainOfResponsibility</AssemblyName>
+    <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="AddHandler.cs" />
+    <Compile Include="CalcHandler.cs" />
+    <Compile Include="CalcType.cs" />
+    <Compile Include="Client.cs" />
+    <Compile Include="DivideHandler.cs" />
+    <Compile Include="MultiplyHandler.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="SubtractHandler.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

DesignPattern/ChainOfResponsibility/Client.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal class Client
+    {
+        public static void HowToUse()
+        {
+            CalcHandler add = new AddHandler();
+            CalcHandler sub = new SubtractHandler();
+            CalcHandler mul = new MultiplyHandler();
+            CalcHandler div = new DivideHandler();
+
+            add.Next = sub;
+            sub.Next = mul;
+            mul.Next = div;
+
+            int result = add.Calculate(CalcType.Multiply, 10, 20);
+            Console.WriteLine(result);
+        }
+    }
+}

DesignPattern/ChainOfResponsibility/DivideHandler.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal class DivideHandler : CalcHandler
+    {
+        public override int Calculate(CalcType cType, int a, int b)
+        {
+            if (cType == CalcType.Divide)
+                return a + b;
+            else
+                return Next.Calculate(cType, a, b);
+        }
+    }
+}

DesignPattern/ChainOfResponsibility/MultiplyHandler.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal class MultiplyHandler : CalcHandler
+    {
+        public override int Calculate(CalcType cType, int a, int b)
+        {
+            if (cType == CalcType.Multiply)
+                return a * b;
+            else
+                return Next.Calculate(cType, a, b);
+        }
+    }
+}

DesignPattern/ChainOfResponsibility/Program.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    /*
+     * 카테고리: 행위 패턴
+     * 개요: 명령을 처리하기 위해 명령을 체인을 따라 전달하며
+     * 그 명령을 수행할 수 있도록 체인으로 연결된 객체에서 처리함
+     * 각 체인의 객체는 명령을 수행해보고 처리할 수 없으면 다음 객체로 넘기며
+     * 명령은 체인의 처음부터 끝까지 계속 이동하게 됨
+     */
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Client.HowToUse();
+
+            Console.ReadKey();
+        }
+    }
+}

DesignPattern/ChainOfResponsibility/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// 어셈블리에 대한 일반 정보는 다음 특성 집합을 통해 
+// 제어됩니다. 어셈블리와 관련된 정보를 수정하려면
+// 이러한 특성 값을 변경하세요.
+[assembly: AssemblyTitle("ChainOfResponsibility")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("ChainOfResponsibility")]
+[assembly: AssemblyCopyright("Copyright ©  2022")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// ComVisible을 false로 설정하면 이 어셈블리의 형식이 COM 구성 요소에 
+// 표시되지 않습니다. COM에서 이 어셈블리의 형식에 액세스하려면
+// 해당 형식에 대해 ComVisible 특성을 true로 설정하세요.
+[assembly: ComVisible(false)]
+
+// 이 프로젝트가 COM에 노출되는 경우 다음 GUID는 typelib의 ID를 나타냅니다.
+[assembly: Guid("808a59ea-ef38-4d24-b4c9-add93d21eddc")]
+
+// 어셈블리의 버전 정보는 다음 네 가지 값으로 구성됩니다.
+//
+//      주 버전
+//      부 버전 
+//      빌드 번호
+//      수정 버전
+//
+// 모든 값을 지정하거나 아래와 같이 '*'를 사용하여 빌드 번호 및 수정 번호를
+// 기본값으로 할 수 있습니다.
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

DesignPattern/ChainOfResponsibility/SubtractHandler.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ChainOfResponsibility
+{
+    internal class SubtractHandler : CalcHandler
+    {
+        public override int Calculate(CalcType cType, int a, int b)
+        {
+            if (cType == CalcType.Subtract)
+                return a - b;
+            else
+                return Next.Calculate(cType, a, b);
+        }
+    }
+}

DesignPattern/Command/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8.1" />
+    </startup>
+</configuration>

DesignPattern/Command/Client.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Command
+{
+    internal class Client
+    {
+        public static void HowToUse()
+        {
+            // Receiver 객체
+            StockBroker broker = new StockBroker();
+
+            // Invoker 객체
+            User user = new User();
+
+            // Command 객체
+            ICommand command = new StockCommand(broker, "MSFT", TxType.Buy, 150);
+
+            user.AddCommand(command);
+            user.AddCommand(broker, "AMZN", TxType.Sell, 2000);
+
+            // Command 실행 요청
+            user.ExecuteAll();
+        }
+    }
+}

DesignPattern/Command/Command.csproj

@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{F34D75D4-7025-4CE3-AF7F-11117FA32F8B}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>Command</RootNamespace>
+    <AssemblyName>Command</AssemblyName>
+    <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Client.cs" />
+    <Compile Include="ICommand.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="StockBroker.cs" />
+    <Compile Include="StockCommand.cs" />
+    <Compile Include="TxType.cs" />
+    <Compile Include="User.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

DesignPattern/Command/ICommand.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Command
+{
+    internal interface ICommand
+    {
+        void Execute();
+    }
+}

DesignPattern/Command/Program.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Command
+{
+    /*
+     * 카테고리: 행위 패턴
+     * 개요: 어떤 행위를 실행하는 요청을 명령 객체로 캡슐화하여 전달함
+     * 명령 요청을 즉시 요청할 수도 있지만, 명령 객체를 큐에 쌓아 배치로 한번에 실행할 수도 있고,
+     * 반대 명령을 내려 Undo 하는 기능을 제공할 수 있음
+     * 
+     * Invoker: 명령을 실행할 때를 결정
+     * Command: 명령을 표현
+     * Receiver: 명령을 받아 일련의 작업을 수행
+     */
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Client.HowToUse();
+
+            Console.ReadKey();
+        }
+    }
+}

DesignPattern/Command/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// 어셈블리에 대한 일반 정보는 다음 특성 집합을 통해 
+// 제어됩니다. 어셈블리와 관련된 정보를 수정하려면
+// 이러한 특성 값을 변경하세요.
+[assembly: AssemblyTitle("Command")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("Command")]
+[assembly: AssemblyCopyright("Copyright ©  2022")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// ComVisible을 false로 설정하면 이 어셈블리의 형식이 COM 구성 요소에 
+// 표시되지 않습니다. COM에서 이 어셈블리의 형식에 액세스하려면
+// 해당 형식에 대해 ComVisible 특성을 true로 설정하세요.
+[assembly: ComVisible(false)]
+
+// 이 프로젝트가 COM에 노출되는 경우 다음 GUID는 typelib의 ID를 나타냅니다.
+[assembly: Guid("f34d75d4-7025-4ce3-af7f-11117fa32f8b")]
+
+// 어셈블리의 버전 정보는 다음 네 가지 값으로 구성됩니다.
+//
+//      주 버전
+//      부 버전 
+//      빌드 번호
+//      수정 버전
+//
+// 모든 값을 지정하거나 아래와 같이 '*'를 사용하여 빌드 번호 및 수정 번호를
+// 기본값으로 할 수 있습니다.
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

DesignPattern/Command/StockBroker.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Command
+{
+    internal class StockBroker
+    {
+        public void Process(string stockSymbol, TxType txType, int qty)
+        {
+            Console.WriteLine($"{txType.ToString()}, {stockSymbol}, {qty}");
+        }
+    }
+}

DesignPattern/Command/StockCommand.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Command
+{
+    internal class StockCommand : ICommand
+    {
+        private StockBroker _broker;
+        private string symbol;
+        private TxType txType;
+        private int qty;
+
+        public StockCommand(StockBroker broker, string symbol, TxType txType, int qty)
+        {
+            _broker = broker;
+            this.symbol = symbol;
+            this.txType = txType;
+            this.qty = qty;
+        }
+
+        public void Execute()
+        {
+            _broker.Process(symbol, txType, qty);
+        }
+    }
+}

DesignPattern/Command/TxType.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Command
+{
+    internal enum TxType
+    {
+        Buy,
+        Sell,
+    }
+}

DesignPattern/Command/User.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Command
+{
+    internal class User
+    {
+        private List<ICommand> _commands = new List<ICommand>();
+
+        public void AddCommand(ICommand command)
+        {
+            _commands.Add(command);
+        }
+
+        public void AddCommand(StockBroker broker, string symbol, TxType txType, int qty)
+        {
+            ICommand command = new StockCommand(broker, symbol, txType, qty);
+            _commands.Add(command);
+        }
+
+        public void ExecuteAll()
+        {
+            foreach (ICommand cmd in _commands)
+            {
+                cmd.Execute();
+            }
+        }
+    }
+}

DesignPattern/DesignPattern.sln

@@ -33,6 +33,16 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Observer", "Observer\Observ
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Strategy", "Strategy\Strategy.csproj", "{D6B55743-F509-4B6C-820A-DB8BC5FA0CE5}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ChainOfResponsibility", "ChainOfResponsibility\ChainOfResponsibility.csproj", "{808A59EA-EF38-4D24-B4C9-ADD93D21EDDC}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Command", "Command\Command.csproj", "{F34D75D4-7025-4CE3-AF7F-11117FA32F8B}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Template", "Template\Template.csproj", "{8C1CA345-A2D4-46E2-9FD0-34E8BE4CE7C4}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "State", "State\State.csproj", "{008D8C56-8546-4EB1-83C6-68FAF2051895}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "State-VendingMachineExample", "State-VendingMachineExample\State-VendingMachineExample.csproj", "{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -99,6 +109,26 @@ Global
 		{D6B55743-F509-4B6C-820A-DB8BC5FA0CE5}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{D6B55743-F509-4B6C-820A-DB8BC5FA0CE5}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{D6B55743-F509-4B6C-820A-DB8BC5FA0CE5}.Release|Any CPU.Build.0 = Release|Any CPU
+		{808A59EA-EF38-4D24-B4C9-ADD93D21EDDC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{808A59EA-EF38-4D24-B4C9-ADD93D21EDDC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{808A59EA-EF38-4D24-B4C9-ADD93D21EDDC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{808A59EA-EF38-4D24-B4C9-ADD93D21EDDC}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F34D75D4-7025-4CE3-AF7F-11117FA32F8B}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F34D75D4-7025-4CE3-AF7F-11117FA32F8B}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F34D75D4-7025-4CE3-AF7F-11117FA32F8B}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F34D75D4-7025-4CE3-AF7F-11117FA32F8B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{8C1CA345-A2D4-46E2-9FD0-34E8BE4CE7C4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8C1CA345-A2D4-46E2-9FD0-34E8BE4CE7C4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8C1CA345-A2D4-46E2-9FD0-34E8BE4CE7C4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8C1CA345-A2D4-46E2-9FD0-34E8BE4CE7C4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{008D8C56-8546-4EB1-83C6-68FAF2051895}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{008D8C56-8546-4EB1-83C6-68FAF2051895}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{008D8C56-8546-4EB1-83C6-68FAF2051895}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{008D8C56-8546-4EB1-83C6-68FAF2051895}.Release|Any CPU.Build.0 = Release|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

DesignPattern/State-VendingMachineExample/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8.1" />
+    </startup>
+</configuration>

DesignPattern/State-VendingMachineExample/Client.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class Client
+    {
+        public static void HowToTest()
+        {
+            VendingMachine vm = new VendingMachine();
+            vm.AddMoney(1);
+            vm.AddMoney(1);
+            vm.AddMoney(1);
+            vm.AddMoney(1);
+            vm.SelectItem(101);
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/DispenseChangeState.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class DispenseChangeState : VMState
+    {
+        public DispenseChangeState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            // Return charge here
+            if (vendingMachine.Money > 0)
+            {
+                Console.WriteLine($"Return charge ${money}");
+                vendingMachine.Money -= money;
+            }
+
+            vendingMachine.State = vendingMachine.ReadyState;
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            throw new ApplicationException();
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/DispenseItemState.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class DispenseItemState : VMState
+    {
+        public DispenseItemState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            decimal? price = vendingMachine.GetPrice(itemId).Value;
+
+            // Dispense item here
+            Console.WriteLine($"Dispense Item#{itemId} ({price.Value})");
+
+            vendingMachine.Money -= price.Value;
+
+            vendingMachine.State = vendingMachine.DispenseChangeState;
+            vendingMachine.State.ReturnChange(vendingMachine.Money);
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/HasMoneyState.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class HasMoneyState : VMState
+    {
+        public HasMoneyState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            vendingMachine.Money += money;
+            Console.WriteLine($"Add ${money}, Balance: {vendingMachine.Money}");
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            decimal? price = vendingMachine.GetPrice(itemId).Value;
+            if (!price.HasValue)
+            {
+                Console.WriteLine($"{itemId} not found");
+                return;
+            }
+
+            if (vendingMachine.Money < price.Value)
+            {
+                Console.WriteLine("Insufficient money");
+                return;
+            }
+
+            vendingMachine.State = vendingMachine.DispenseItemState;
+            vendingMachine.State.SelectItem(itemId);
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/Product.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class Product
+    {
+        private List<Item> items;
+
+        public Product()
+        {
+            items = new List<Item>()
+            {
+                new Item() { Id = 101, Price = 3.50M },
+                new Item() { Id = 201, Price = 4.50M },
+                new Item() { Id = 301, Price = 4.50M }
+            };
+        }
+
+        public decimal? GetPrice(int itemId)
+        {
+            Item item = items.SingleOrDefault(x => x.Id == itemId);
+
+            return item == null ? null : (decimal?)item.Price;
+        }
+
+        private class Item
+        {
+            public int Id { get; set; }
+            public decimal Price { get; set; }
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/Program.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Client.HowToTest();
+
+            Console.ReadKey();
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// 어셈블리에 대한 일반 정보는 다음 특성 집합을 통해 
+// 제어됩니다. 어셈블리와 관련된 정보를 수정하려면
+// 이러한 특성 값을 변경하세요.
+[assembly: AssemblyTitle("State-VendingMachineExample")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("State-VendingMachineExample")]
+[assembly: AssemblyCopyright("Copyright ©  2022")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// ComVisible을 false로 설정하면 이 어셈블리의 형식이 COM 구성 요소에 
+// 표시되지 않습니다. COM에서 이 어셈블리의 형식에 액세스하려면
+// 해당 형식에 대해 ComVisible 특성을 true로 설정하세요.
+[assembly: ComVisible(false)]
+
+// 이 프로젝트가 COM에 노출되는 경우 다음 GUID는 typelib의 ID를 나타냅니다.
+[assembly: Guid("ed14b6e2-04bb-4f77-80e7-c5f0e945b750")]
+
+// 어셈블리의 버전 정보는 다음 네 가지 값으로 구성됩니다.
+//
+//      주 버전
+//      부 버전 
+//      빌드 번호
+//      수정 버전
+//
+// 모든 값을 지정하거나 아래와 같이 '*'를 사용하여 빌드 번호 및 수정 번호를
+// 기본값으로 할 수 있습니다.
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

DesignPattern/State-VendingMachineExample/ReadyState.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    // Concrete State
+    internal class ReadyState : VMState
+    {
+        public ReadyState(VendingMachine context)
+        {
+            vendingMachine = context;
+        }
+
+        public override void AddMoney(decimal money)
+        {
+            vendingMachine.State = vendingMachine.HasMoneyState;
+            vendingMachine.State.AddMoney(money);
+        }
+
+        public override void ReturnChange(decimal money)
+        {
+            throw new ApplicationException();
+        }
+
+        public override void SelectItem(int itemId)
+        {
+            throw new ApplicationException();
+        }
+    }
+}

DesignPattern/State-VendingMachineExample/State-VendingMachineExample.csproj

@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{ED14B6E2-04BB-4F77-80E7-C5F0E945B750}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>State_VendingMachineExample</RootNamespace>
+    <AssemblyName>State-VendingMachineExample</AssemblyName>
+    <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Client.cs" />
+    <Compile Include="DispenseChangeState.cs" />
+    <Compile Include="DispenseItemState.cs" />
+    <Compile Include="HasMoneyState.cs" />
+    <Compile Include="Product.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="ReadyState.cs" />
+    <Compile Include="VendingMachine.cs" />
+    <Compile Include="VMState.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

DesignPattern/State-VendingMachineExample/VMState.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    // State 인터페이스
+    internal abstract class VMState
+    {
+        protected VendingMachine vendingMachine;
+        public abstract void AddMoney(decimal money);
+        public abstract void SelectItem(int itemId);
+        public abstract void ReturnChange(decimal money);
+    }
+}

DesignPattern/State-VendingMachineExample/VendingMachine.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State_VendingMachineExample
+{
+    // Context
+    internal class VendingMachine
+    {
+        private Product product = new Product();
+        internal decimal Money { get; set; }
+
+        internal VMState State { get; set; }
+
+        internal VMState ReadyState { get; private set; } 
+        internal VMState HasMoneyState { get; private set; } 
+        internal VMState DispenseItemState { get; private set; } 
+        internal VMState DispenseChangeState { get; private set; } 
+
+        public VendingMachine()
+        {
+            this.Money = 0;
+            this.ReadyState = new ReadyState(this);
+            this.HasMoneyState = new HasMoneyState(this);
+            this.DispenseItemState = new DispenseItemState(this);
+            this.DispenseChangeState = new DispenseChangeState(this);
+            this.State = this.ReadyState;
+        }
+
+        public void AddMoney(decimal money)
+        {
+            this.State.AddMoney(money);
+        }
+
+        public void SelectItem(int itemId)
+        {
+            this.State.SelectItem(itemId);
+        }
+
+        internal decimal? GetPrice(int itemId)
+        {
+            return product.GetPrice(itemId);
+        }
+    }
+}

DesignPattern/State/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8.1" />
+    </startup>
+</configuration>

DesignPattern/State/BadState.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State
+{
+    internal class BadState : State
+    {
+        public BadState()
+        {
+            this.InterestRate = 35.00M;
+        }
+
+        public override void ChangeScore(Context context, int score)
+        {
+            if (score >= 600)
+            {
+                context.CurrentState = new NormalState();
+
+                context.CurrentState.ChangeScore(context, score);
+            }
+        }
+    }
+}

DesignPattern/State/Client.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State
+{
+    internal class Client
+    {
+        public static void HowToTest()
+        {
+            Context ctx = new Context();
+            ctx.SetCreditScore(550);
+            Console.WriteLine($"{ctx.CurrentState.InterestRate}%");
+
+            ctx.SetCreditScore(760);
+            Console.WriteLine($"{ctx.CurrentState.InterestRate}%");
+        }
+    }
+}

DesignPattern/State/Context.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State
+{
+    internal class Context
+    {
+        public State CurrentState { get; set; }
+
+        public Context()
+        {
+            this.CurrentState = new NormalState();
+        }
+
+        public void SetCreditScore(int creditScore)
+        {
+            Console.WriteLine($"{creditScore}");
+            this.CurrentState.ChangeScore(this, creditScore);
+        }
+    }
+}

DesignPattern/State/NormalState.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State
+{
+    internal class NormalState : State
+    {
+        public NormalState()
+        {
+            this.InterestRate = 25.00M;
+        }
+
+        public override void ChangeScore(Context context, int score)
+        {
+            if (score < 600)
+            {
+                context.CurrentState = new BadState();
+
+                context.CurrentState.ChangeScore(context, score);
+            }
+            else if (score >= 750)
+            {
+                context.CurrentState = new VIPState();
+
+                context.CurrentState.ChangeScore(context, score);
+            }
+        }
+    }
+}

DesignPattern/State/Program.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State
+{
+    /*
+     * 카테고리: 행위 패턴
+     * 개요: 상태별 행위를 별도의 클래스에 구현하여
+     * 복잡한 상태별 행위를 효율적으로 분리하여 구현하고
+     * 새로운 상태에 따른 행위를 유연하게 추가/확장함
+     * 
+     * Context: 현재 상태를 기억
+     * State: 인터페이스
+     * Concrete State: 각 상태별 행위 구현
+     */
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Client.HowToTest();
+
+            Console.ReadKey();
+        }
+    }
+}

DesignPattern/State/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// 어셈블리에 대한 일반 정보는 다음 특성 집합을 통해 
+// 제어됩니다. 어셈블리와 관련된 정보를 수정하려면
+// 이러한 특성 값을 변경하세요.
+[assembly: AssemblyTitle("State")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("State")]
+[assembly: AssemblyCopyright("Copyright ©  2022")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// ComVisible을 false로 설정하면 이 어셈블리의 형식이 COM 구성 요소에 
+// 표시되지 않습니다. COM에서 이 어셈블리의 형식에 액세스하려면
+// 해당 형식에 대해 ComVisible 특성을 true로 설정하세요.
+[assembly: ComVisible(false)]
+
+// 이 프로젝트가 COM에 노출되는 경우 다음 GUID는 typelib의 ID를 나타냅니다.
+[assembly: Guid("008d8c56-8546-4eb1-83c6-68faf2051895")]
+
+// 어셈블리의 버전 정보는 다음 네 가지 값으로 구성됩니다.
+//
+//      주 버전
+//      부 버전 
+//      빌드 번호
+//      수정 버전
+//
+// 모든 값을 지정하거나 아래와 같이 '*'를 사용하여 빌드 번호 및 수정 번호를
+// 기본값으로 할 수 있습니다.
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

DesignPattern/State/State.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State
+{
+    internal abstract class State
+    {
+        public decimal InterestRate { get; protected set; }
+
+        public abstract void ChangeScore(Context context, int score);
+    }
+}

DesignPattern/State/State.csproj

@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{008D8C56-8546-4EB1-83C6-68FAF2051895}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>State</RootNamespace>
+    <AssemblyName>State</AssemblyName>
+    <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="BadState.cs" />
+    <Compile Include="Client.cs" />
+    <Compile Include="Context.cs" />
+    <Compile Include="NormalState.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="State.cs" />
+    <Compile Include="VIPState.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

DesignPattern/State/VIPState.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State
+{
+    internal class VIPState : State
+    {
+        public VIPState()
+        {
+            this.InterestRate = 15.00M;
+        }
+
+        public override void ChangeScore(Context context, int score)
+        {
+            if (score < 750)
+            {
+                context.CurrentState = new NormalState();
+
+                context.CurrentState.ChangeScore(context, score);
+            }
+        }
+    }
+}

DesignPattern/Template/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.8.1" />
+    </startup>
+</configuration>

DesignPattern/Template/Client.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Template
+{
+    internal class Client
+    {
+        public static void HowToTest()
+        {
+            Letter letter = new SalesLetter();
+            letter.Send();
+
+            letter = new OfferLetter();
+            letter.Send();
+        }
+    }
+}

DesignPattern/Template/Letter.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Template
+{
+    // 베이스클래스
+    internal abstract class Letter
+    {
+        public void Send()
+        {
+            CompanyLogo();
+            Greeting();
+
+            Message();
+            Offer();
+
+            Ending();
+            Footer();
+        }
+
+        // 필수
+        public abstract void Message();
+
+        // 옵션
+        public virtual void Offer() { }
+
+
+        // 고정 메서드 들
+        private void CompanyLogo()
+        {
+            Console.WriteLine("COMPANY LOGO");
+        }
+
+        private void Greeting()
+        {
+            Console.WriteLine("HELLO");
+        }
+
+        private void Ending()
+        {
+            Console.WriteLine("BYE");
+        }
+
+        private void Footer()
+        {
+            Console.WriteLine("WARM REGARD");
+        }
+    }
+}

DesignPattern/Template/OfferLetter.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Template
+{
+    internal class OfferLetter : Letter
+    {
+        public override void Message()
+        {
+            Console.WriteLine("This is offer letter");
+        }
+
+        public override void Offer()
+        {
+            Console.WriteLine("This is our offer");
+        }
+    }
+}

DesignPattern/Template/Program.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Template
+{
+    /*
+     * 카테고리: 행위 패턴
+     * 개요: 메서드 중 일부 로직을 하위 서브클래스에서 재정의하도록 함
+     * 베이스클래스에서 기본 골격 템플릿 코드를 만들어두고 서브클래스에서 일부 로직을 추가/수정함
+     */
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Client.HowToTest();
+
+            Console.ReadKey();
+        }
+    }
+}

DesignPattern/Template/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// 어셈블리에 대한 일반 정보는 다음 특성 집합을 통해 
+// 제어됩니다. 어셈블리와 관련된 정보를 수정하려면
+// 이러한 특성 값을 변경하세요.
+[assembly: AssemblyTitle("Template")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("Template")]
+[assembly: AssemblyCopyright("Copyright ©  2022")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// ComVisible을 false로 설정하면 이 어셈블리의 형식이 COM 구성 요소에 
+// 표시되지 않습니다. COM에서 이 어셈블리의 형식에 액세스하려면
+// 해당 형식에 대해 ComVisible 특성을 true로 설정하세요.
+[assembly: ComVisible(false)]
+
+// 이 프로젝트가 COM에 노출되는 경우 다음 GUID는 typelib의 ID를 나타냅니다.
+[assembly: Guid("8c1ca345-a2d4-46e2-9fd0-34e8be4ce7c4")]
+
+// 어셈블리의 버전 정보는 다음 네 가지 값으로 구성됩니다.
+//
+//      주 버전
+//      부 버전 
+//      빌드 번호
+//      수정 버전
+//
+// 모든 값을 지정하거나 아래와 같이 '*'를 사용하여 빌드 번호 및 수정 번호를
+// 기본값으로 할 수 있습니다.
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

DesignPattern/Template/SalesLetter.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Template
+{
+    internal class SalesLetter : Letter
+    {
+        public override void Message()
+        {
+            Console.WriteLine("This is sales letter");
+        }
+    }
+}

DesignPattern/Template/Template.csproj

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{8C1CA345-A2D4-46E2-9FD0-34E8BE4CE7C4}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>Template</RootNamespace>
+    <AssemblyName>Template</AssemblyName>
+    <TargetFrameworkVersion>v4.8.1</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Client.cs" />
+    <Compile Include="Letter.cs" />
+    <Compile Include="OfferLetter.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="SalesLetter.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>