How to extend C# built-in types, like String?

Question

Greetings everyone... I need to Trim a String. But I want to remove all the repeated blank spaces within the String itself, not only at the end or at the start of it. I could do it with a method like:

public static string ConvertWhitespacesToSingleSpaces(string value)
{
    value = Regex.Replace(value, @"\s+", " ");
}

Which I got from here. But I want this piece of code to be called within the String.Trim() itself, so I think I need to extend or overload or override the Trim method... Is there a way to do that?

Thanks in advance.

Answer 1

Since you cannot extend string.Trim(). You could make an Extension method as described here that trims and reduces whitespace.

namespace CustomExtensions
{
    //Extension methods must be defined in a static class
    public static class StringExtension
    {
        // This is the extension method.
        // The first parameter takes the "this" modifier
        // and specifies the type for which the method is defined.
        public static string TrimAndReduce(this string str)
        {
            return ConvertWhitespacesToSingleSpaces(str).Trim();
        }

        public static string ConvertWhitespacesToSingleSpaces(this string value)
        {
            return Regex.Replace(value, @"\s+", " ");
        }
    }
}

You can use it like so

using CustomExtensions;

string text = "  I'm    wearing the   cheese.  It isn't wearing me!   ";
text = text.TrimAndReduce();

Gives you

text = "I'm wearing the cheese. It isn't wearing me!";