C# – add extension methods to an existing static class

cextension-methodsstatic

I'm a fan of extension methods in C#, but haven't had any success adding an extension method to a static class, such as Console.

For example, if I want to add an extension to Console, called 'WriteBlueLine', so that I can go:

Console.WriteBlueLine("This text is blue");

I tried this by adding a local, public static method, with Console as a 'this' parameter… but no dice! 

public static class Helpers {
    public static void WriteBlueLine(this Console c, string text)
    {
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.WriteLine(text);
        Console.ResetColor();
    }
}

This didn't add a 'WriteBlueLine' method to Console… am I doing it wrong? Or asking for the impossible?

Best Answer

No. Extension methods require an instance variable (value) for an object. You can however, write a static wrapper around the ConfigurationManager interface. If you implement the wrapper, you don't need an extension method since you can just add the method directly.

 public static class ConfigurationManagerWrapper
 {
      public static ConfigurationSection GetSection( string name )
      {
         return ConfigurationManager.GetSection( name );
      }

      .....

      public static ConfigurationSection GetWidgetSection()
      {
          return GetSection( "widgets" );
      }
 }
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