command

DesignPattern/DesignPattern.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.31903.59
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DesignPattern", "DesignPattern\DesignPattern.csproj", "{E7881A12-006C-4464-8ADE-BC952AE99FEF}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{E7881A12-006C-4464-8ADE-BC952AE99FEF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E7881A12-006C-4464-8ADE-BC952AE99FEF}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E7881A12-006C-4464-8ADE-BC952AE99FEF}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E7881A12-006C-4464-8ADE-BC952AE99FEF}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

DesignPattern/DesignPattern/DesignPattern.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

DesignPattern/DesignPattern/Patterns/CommandPattern.cs

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+namespace DesignPattern.Patterns
+{
+    interface ICommand
+    {
+        void Execute();
+    }
+
+    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 cmd = new StockCommand(broker, symbol, txType, qty);
+            _commands.Add(cmd);
+        }
+
+        public void ExecuteAll()
+        {
+            foreach (var cmd in _commands)
+            {
+                cmd.Execute();
+            }
+        }
+    }
+
+    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;
+            _symbol = symbol;
+            _txType = txType;
+            _qty = qty;
+        }
+
+        public void Execute()
+        {
+            _broker.Process(_symbol, _txType, _qty);
+        }
+    }
+
+    enum TxType
+    {
+        Buy,
+        Sell
+    }
+
+    class StockBroker
+    {
+        public void Process(string stockSymbol, TxType txType, int qty)
+        {
+            Console.WriteLine($"{txType}, {stockSymbol}, {qty}");
+        }
+    }
+
+    class CommandClient
+    {
+        public static void Work()
+        {
+            var broker = new StockBroker();
+
+            User user = new User();
+
+            ICommand cmd = new StockCommand(broker, "MSFT", TxType.Buy, 150);
+            user.AddCommand(cmd);
+            user.AddCommand(broker, "AMZN", TxType.Sell, 2000);
+            user.AddCommand(broker, "BRK.B", TxType.Buy, 5000);
+            user.AddCommand(broker, "APPL", TxType.Sell, 1000);
+
+            user.ExecuteAll();
+        }
+    }
+}

DesignPattern/DesignPattern/Patterns/FactoryPattern.cs

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+using System.Runtime.CompilerServices;
+
+namespace DesignPattern.Patterns
+{
+    public interface IProduct
+    {
+        string Operation();
+    }
+
+    abstract class Creator
+    {
+        public abstract IProduct FactoryMethod();
+
+        public string SomeOperation()
+        {
+            var product = FactoryMethod();
+
+            var result = $"Creator: The same creator's code has just worked with {product.Operation()}";
+
+            return result;
+        }
+    }
+
+    class ContreteProduct1 : IProduct
+    {
+        public string Operation()
+        {
+            return $"[Result of {this.GetType().Name}]";
+        }
+    }
+
+    class ContreteProduct2 : IProduct
+    {
+        public string Operation()
+        {
+            return $"[Result of {this.GetType().Name}]";
+        }
+    }
+
+    class ConcreteCreator1 : Creator
+    {
+        public override IProduct FactoryMethod()
+        {
+            return new ContreteProduct1();
+        }
+    }
+
+    class ConcreteCreator2 : Creator
+    {
+        public override IProduct FactoryMethod()
+        {
+            return new ContreteProduct2();
+        }
+    }
+
+    class FactoryClient
+    {
+        public static void Work()
+        {
+            Console.WriteLine("App: Launch with the Creator1");
+            ClientCode(new ConcreteCreator1());
+
+            Console.WriteLine();
+
+            Console.WriteLine("App: Launch with the Creator2");
+            ClientCode(new ConcreteCreator2());
+        }
+
+        public static void ClientCode(Creator creator)
+        {
+            Console.WriteLine($"Client: I'm not aware of the creator's class, but it still works.");
+            Console.WriteLine(creator.SomeOperation());
+        }
+    }
+}

DesignPattern/DesignPattern/Program.cs

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+using DesignPattern.Patterns;
+
+namespace DesignPattern;
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        // FactoryClient.Work();
+
+        CommandClient.Work();
+    }
+}