Trimming String C#.NET, ASP.NET Remove all extra space

Task:  Remove Extra spacing from a string(paragraph). Trimming the space from String.

Description:  Here I create a code for removing extra space from a string as Trimming externally and as well as internally also. So that two and more consecutive space will remove.

C#.NET,SQL SERVER, ASP.NET HELP

      public string replacespace(string s)

    {

        int l = s.Length;

        char[] ch = s.ToCharArray();

        s = "";

        for (int i = 0; i < l - 1; i++)

        {

            if (ch[i] == ' ')

            {

                if (ch[i + 1] == ' ')

                { }

                else

                    s = s + ch[i];

            }

            else

                s = s + ch[i];

        }

        if (ch[l - 1] != ' ')

            s = s + ch[l - 1];

        return (s);

    }