command pattern example

Author: anupavanm

CommandPattern/CommandPattern.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>

CommandPattern/Program.cs

@@ -0,0 +1,102 @@
+using System;
+
+namespace CommandPattern
+{
+  class Program
+  {
+    // Receiver
+    class Bulb
+    {
+      public void TurnOn()
+      {
+        Console.WriteLine("Bulb has been lit");
+      }
+
+      public void TurnOff()
+      {
+        Console.WriteLine("Darkness!");
+      }
+    }
+
+    interface ICommand
+    {
+      void Execute();
+      void Undo();
+      void Redo();
+    }
+
+    // Command
+    class TurnOn : ICommand
+    {
+      private Bulb mBulb;
+
+      public TurnOn(Bulb bulb)
+      {
+        mBulb = bulb ?? throw new ArgumentNullException("Bulb", "Bulb cannot be null");
+      }
+
+      public void Execute()
+      {
+        mBulb.TurnOn();
+      }
+
+      public void Undo()
+      {
+        mBulb.TurnOff();
+      }
+
+      public void Redo()
+      {
+        Execute();
+      }
+    }
+
+    class TurnOff : ICommand
+    {
+      private Bulb mBulb;
+
+      public TurnOff(Bulb bulb)
+      {
+        mBulb = bulb ?? throw new ArgumentNullException("Bulb", "Bulb cannot be null");
+      }
+
+      public void Execute()
+      {
+        mBulb.TurnOff();
+      }
+
+      public void Undo()
+      {
+        mBulb.TurnOn();
+      }
+
+      public void Redo()
+      {
+        Execute();
+      }
+    }
+
+    // Invoker
+    class RemoteControl
+    {
+      public void Submit(ICommand command)
+      {
+        command.Execute();
+      }
+    }
+
+    static void Main(string[] args)
+    {
+      var bulb = new Bulb();
+
+      var turnOn = new TurnOn(bulb);
+      var turnOff = new TurnOff(bulb);
+
+      var remote = new RemoteControl();
+      remote.Submit(turnOn); // Bulb has been lit!
+      remote.Submit(turnOff); // Darkness!
+
+      Console.ReadLine();
+    }
+  }
+}

DesignPatterns.sln

@@ -29,6 +29,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ProxyPattern", "ProxyPatter
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ChainOfResponsibilityPattern", "ChainOfResponsibilityPattern\ChainOfResponsibilityPattern.csproj", "{E94F9FB8-B495-4A85-BAB4-0B08C69BA2D9}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CommandPattern", "CommandPattern\CommandPattern.csproj", "{25E92DA1-1205-4D53-85F4-B77BC92DCF5A}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -87,6 +89,10 @@ Global
 		{E94F9FB8-B495-4A85-BAB4-0B08C69BA2D9}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{E94F9FB8-B495-4A85-BAB4-0B08C69BA2D9}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{E94F9FB8-B495-4A85-BAB4-0B08C69BA2D9}.Release|Any CPU.Build.0 = Release|Any CPU
+		{25E92DA1-1205-4D53-85F4-B77BC92DCF5A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{25E92DA1-1205-4D53-85F4-B77BC92DCF5A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{25E92DA1-1205-4D53-85F4-B77BC92DCF5A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{25E92DA1-1205-4D53-85F4-B77BC92DCF5A}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE