Format a double value like currency but without the currency sign (C#)

I feed a textbox a string value showing me a balance that need to be formatted like this: ``` ###,###,###,##0.00 ``` I could use the value.ToString("c"), but this would put the currency sign in front of it. Any idea how I would manipulate the string before feeding the textbox to achieve the above formatting? I tried this, without success: ``` String.Format("###,###,###,##0.00", currentBalance); ``` Many Thanks,