using string format for a credit card number

Question

I'm trying to display a credit card number as a string like #### #### #### ####

I tried:

txtbox.Text = string.Format("{0:#### #### #### ####}", ccNumber);

and it didn't work. Any ideas?

Answer 1

String.Format("{0:0000 0000 0000 0000}", number)

EDIT

I paste my comment here to made it readable:

ccNumber is an Int or a string? if it's an int it should work. if it's a string you need to do a

String.Format("{0:0000 0000 0000 0000}", (Int64.Parse("1234567812345678")))

Answer 2

You better you a masked textBox, and set the mask to:

 this.maskedTextBox1.Mask = "0000 0000 0000 0000";

or set the string format to:

 long number = 1234123412341234;
 textBox1.Text = String.Format("{0:0000 0000 0000 0000}", number);