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?

Solution 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")))

Solution 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);

Solution 3

ccNumber.ToString("#### #### #### ####")

Comments

[FiveTools]

I expect the string to have a space after four digits - 1234 5678 9123 4567 - and it looks like 1234567891234567.

[dcarneiro]

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")))

[FiveTools]

Make sure the number is not already in string format! once I converted to long, it worked as expected.

[Chris Marisic]

Major issue with using this though is all leading and trailing 0s will be destroyed.

[dcarneiro]

@Chris Marisic String.Format only cuts leading and trailing zeros if you format with #### instead of 0000.

[Chris Marisic]

Arguably String.Format("{0:0000 0000 0000 0000}", number) is even more nefarious since that will turn a 15 digit CC into a 16 digit CC etc.

[live-love]

That doesn't work for 20 digit credit cards (Int64.Parse overflow)