state

DesignPatternGuru/DesignPatternGuru.sln

@@ -45,6 +45,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Memonto", "Memonto\Memonto.
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Observer", "Observer\Observer.csproj", "{EB189FAC-7C63-48BB-92D7-3C35A277EA1D}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "State", "State\State.csproj", "{BE9AFB6B-3AD5-4F54-91FF-7829B0FBFBCD}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -123,6 +125,10 @@ Global
 		{EB189FAC-7C63-48BB-92D7-3C35A277EA1D}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{EB189FAC-7C63-48BB-92D7-3C35A277EA1D}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{EB189FAC-7C63-48BB-92D7-3C35A277EA1D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BE9AFB6B-3AD5-4F54-91FF-7829B0FBFBCD}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BE9AFB6B-3AD5-4F54-91FF-7829B0FBFBCD}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BE9AFB6B-3AD5-4F54-91FF-7829B0FBFBCD}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BE9AFB6B-3AD5-4F54-91FF-7829B0FBFBCD}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -146,6 +152,7 @@ Global
 		{08D296F6-6698-4FCB-B605-318D9381F975} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
 		{A6E39678-6214-4BD2-B616-A3350340E5AB} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
 		{EB189FAC-7C63-48BB-92D7-3C35A277EA1D} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
+		{BE9AFB6B-3AD5-4F54-91FF-7829B0FBFBCD} = {E3B8A482-1A9A-4B6E-8310-050A44C8E379}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {3E5A9C6B-2E8A-466E-B5E0-4379902EFFAC}

DesignPatternGuru/State/Program.cs

@@ -0,0 +1,14 @@
+using State.States;
+
+namespace State
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            var context = new Context(new ConcreteStateA());
+            context.Request1();
+            context.Request2();
+        }
+    }
+}

DesignPatternGuru/State/State.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

DesignPatternGuru/State/States/ConcreteStateA.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State.States
+{
+    internal class ConcreteStateA : State
+    {
+        public override void Handle1()
+        {
+            Console.WriteLine("ConcreteStateA handles request1.");
+            Console.WriteLine("ConcreteStateA wants to change the state of the context.");
+            _context.TransitionTo(new ConcreteStateB());
+        }
+
+        public override void Handle2()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

DesignPatternGuru/State/States/ConcreteStateB.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State.States
+{
+    internal class ConcreteStateB : State
+    {
+        public override void Handle1()
+        {
+            Console.WriteLine("ConcreteStateB handles request1.");
+        }
+
+        public override void Handle2()
+        {
+            Console.WriteLine("ConcreteStateB handles request2.");
+            Console.WriteLine("ConcreteStateB wants to change the state of the context.");
+            _context.TransitionTo(new ConcreteStateA());
+        }
+    }
+}

DesignPatternGuru/State/States/Context.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State.States
+{
+    internal class Context
+    {
+        private State _state = null;
+
+        public Context(State state)
+        {
+            TransitionTo(state);
+        }
+
+        public void TransitionTo(State state)
+        {
+            Console.WriteLine($"Context: Transition to {state.GetType().Name}");
+            _state = state;
+            _state.SetContext(this);
+        }
+
+        public void Request1()
+        {
+            _state.Handle1();
+        }
+
+        public void Request2()
+        {
+            _state.Handle2();
+        }
+    }
+}

DesignPatternGuru/State/States/State.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace State.States
+{
+    abstract class State
+    {
+        protected Context _context;
+
+        public void SetContext(Context context) 
+        { 
+            _context = context; 
+        }
+
+        public abstract void Handle1();
+        
+        public abstract void Handle2();
+    }
+}