Remove whitespace within string

var s = "This   is    a     string    with multiple    white   space";

Regex.Replace(s, @"\s+", " "); // "This is a string with multiple white space"

Regex r = new Regex(@"\s+");
string stripped = r.Replace("Too  many    spaces", " ");

Here's a nice way without regex. With Linq.

var astring = "This           is      a       string  with     to     many   spaces.";
astring = string.Join(" ", astring.Split(' ').Where(m => m != string.Empty));

output "This is a string with to many spaces"