How to insert a thousand separator (comma) with convert to double

Question

I am trying to format the contents of a text box:

this.lblSearchResults1.Text =
    Convert.ToDouble(lblSearchResults1.Text).ToString(); 

H

Answer 1

For complete custom control, use ... .ToString("#,##0.00") or variations thereof. The . and , will be replaced by culture dependent symbols. In most of europe you'd get 1.234,56.
Another useful picture is 0.0#.

To use a pattern depending on the users (or on a selected) culture, use The Numeric ("N") Format Specifier, as in .ToString("N") or "... {0:N}".