state pattern example

Author: anupavanm

DesignPatterns.sln

@@ -43,6 +43,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "VisitorPattern", "VisitorPa
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StrategyPattern", "StrategyPattern\StrategyPattern.csproj", "{FCF7B59D-63F0-4BE3-AE39-3EA7D562A67E}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StatePattern", "StatePattern\StatePattern.csproj", "{606D9229-082C-4A71-8DD3-1918A14B7CF2}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -129,6 +131,10 @@ Global
 		{FCF7B59D-63F0-4BE3-AE39-3EA7D562A67E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{FCF7B59D-63F0-4BE3-AE39-3EA7D562A67E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{FCF7B59D-63F0-4BE3-AE39-3EA7D562A67E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{606D9229-082C-4A71-8DD3-1918A14B7CF2}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{606D9229-082C-4A71-8DD3-1918A14B7CF2}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{606D9229-082C-4A71-8DD3-1918A14B7CF2}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{606D9229-082C-4A71-8DD3-1918A14B7CF2}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

StatePattern/Program.cs

@@ -0,0 +1,84 @@
+using System;
+
+namespace StatePattern
+{
+interface IWritingState {
+
+  void Write(string words);
+
+}
+
+class UpperCase : IWritingState
+{
+  public void Write(string words)
+  {
+    Console.WriteLine(words.ToUpper());
+  }
+}
+
+class LowerCase : IWritingState
+{
+  public void Write(string words)
+  {
+    Console.WriteLine(words.ToLower());
+  }
+}
+
+class DefaultText : IWritingState
+{
+  public void Write(string words)
+  {
+    Console.WriteLine(words);
+  }
+}
+
+class TextEditor {
+
+  private IWritingState mState;
+
+  public TextEditor()
+  {
+    mState = new DefaultText();
+  }
+
+  public void SetState(IWritingState state)
+  {
+    mState = state;
+  }
+
+  public void Type(string words)
+  {
+    mState.Write(words);
+  }
+
+}
+
+  class Program
+  {
+    static void Main(string[] args)
+    {
+      var editor = new TextEditor();
+
+      editor.Type("First line");
+
+      editor.SetState(new UpperCase());
+
+      editor.Type("Second Line");
+      editor.Type("Third Line");
+
+      editor.SetState(new LowerCase());
+
+      editor.Type("Fourth Line");
+      editor.Type("Fifthe Line");
+
+      // Output:
+      // First line
+      // SECOND LINE
+      // THIRD LINE
+      // fourth line
+      // fifth line
+
+      Console.ReadLine();
+    }
+  }
+}

StatePattern/StatePattern.csproj

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