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

Looking at the standard numeric format strings:

You can most easily use 'N' which will do the right thing based on the user culture, so in your case you can just add "N" as a param to the ToString

([double]12345.67).ToString("N")

12,345.67