我可以将扩展方法添加到现有的静态类吗?

Can I add extension methods to an existing static class?(我可以将扩展方法添加到现有的静态类吗?)

问题描述

我是 C# 中的扩展方法的粉丝，但没有成功将扩展方法添加到静态类，例如 Console.

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.

例如，如果我想在Console中添加一个扩展，名为'WriteBlueLine'，这样我就可以去:

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

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

我尝试通过添加一个本地的公共静态方法，将 Console 作为 'this' 参数...但没有骰子！

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();
    }
}

这没有向 Console 添加一个WriteBlueLine"方法...我做错了吗?还是要求不可能的事?

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

推荐答案

没有.扩展方法需要对象的实例变量(值).但是，您可以在 ConfigurationManager 接口周围编写一个静态包装器.如果实现包装器，则不需要扩展方法，因为您可以直接添加方法.

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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