C# format to thousand seperator

Question

I am trying to format user input to a thousand seperator format. I tried the code here, but it keeps breaking the application:

Amt.Text = String.Format("{0:0,0.00}", Convert.ToDouble(Amt));

So when the user inputs 3566412, then it needs to convert automatically to 3,566,412

score 0 · Answer 1 · answered Nov 24 '15 at 10:05

0

You are trying to convert the control (named Amt) to a double, which is a bad idea since you want to convert the text of the control (Amt.Text). I would suggest to use a decimal since that is more precise and will not cause floating point issues:

Amt.Text = String.Format("{0:0,0.00}", Convert.ToDecimal(Amt.Text));

Another thing to consider is to use a control that can mask itself, so you don't need to replace the text yourself every time.

answered Nov 24 '15 at 10:05

Patrick Hofman

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Thank you but when I try it that when and try to input 1500 it changes it to 5.001.00 . it does not keep the same order as I inputted the numbers – Miss R Nov 24 '15 at 11:29
its within my textbox element – Miss R Nov 24 '15 at 12:32
You mean an event handler? What event? – Patrick Hofman Nov 24 '15 at 12:32
private void Amt_TextChanged(object sender, EventArgs e){ Amt.Text = String.Format("{0:0,0.00}", Convert.ToDecimal(Amt.Text)); } – Miss R Nov 24 '15 at 12:32
And you see the cursor flashing when you type slowly and returning to the wrong position? This is why I recommend to use a control that does this for you. – Patrick Hofman Nov 24 '15 at 12:33
how do i use a control? – Miss R Nov 24 '15 at 14:04
I dont see the need for that – Miss R Nov 25 '15 at 10:55

Malte R · Answer 2 · 2015-11-24T10:07:12.790

0

You might want to check out Standard Numeric Format Strings at MSDN

Then you could do something like

Amt.Text = inputnumber.ToString("N");

Which will format 3566412 to 3,566,412.0

If you want to take it directly from the textbox, you could do something like this, which checks if the text can be parsed before setting the text

double result = 0;
if (double.TryParse(Amt.Text, out result)
{
    Amt.Text = result.ToString("N");
}

edited Nov 24 '15 at 10:07

answered Nov 24 '15 at 10:06

Malte R

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That will round the number, right? And what is `inputnumber`? How does it get the value from the control? – Patrick Hofman Nov 24 '15 at 10:06
Thank you but when I try it that when and try to input 1500 it changes it to 5.001.00 . it does not keep the same order as I inputted the numbers – Miss R Nov 24 '15 at 11:26
That sounds very strange, how did it happen? – Malte R Nov 24 '15 at 14:20

C# format to thousand seperator

2 Answers2