string user function

how can i add a custom function to a string type

example:

string test = "hello";

test.userFn("world");

public string userFn(s开发者_如何学JAVAtrng str) {
   return " " + str;
}

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http://msdn.microsoft.com/en-us/library/bb383977.aspx

namespace ExtensionMethods
{
    public static class MyExtensions
    {
        public static string userFn(this string str)
        {
            return " " + str;
        }
    }   
}

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You can't add a custom function, but you can use extension methods to approximate this:

public static class StringExtensions {
    public static string userFn(this string str) {
         return " " + str;
    }
}

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Depends on what framework you are using, if you are using 3.5, then yes you can add extensions to the String class, thereby extending it to include your methods/properties. Have a look here for an example of extending the String class.

Hope this helps, Best regards, Tom.

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You should check .net 3.0 extension methods Here

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Take a look at Extension methods.

Microsoft example:

namespace ExtensionMethods
{
    public static class MyExtensions
    {
        public static int WordCount(this String str)
        {
            return str.Split(new char[] { ' ', '.', '?' }, StringSplitOptions.RemoveEmptyEntries).Length;
        }
    }   
}