Formatting a string to display custom decimal values

You can use string formatting coupled to a simple if condition. To shorten it's use, you can also make it an Extension method. It can look like this :

public static string FormatConditionnaly(this double input)
{
    return input % 1 == 0 ? input.ToString("#,0") : input.ToString("#,0.00");
}

Basically, if you number does not contain any decimals (the % 1 == 0 check), you format it without decimals. If it fails the check, you add the two zeroes.

It is used like that :

const double flatNumber = 1000;
string result1 = flatNumber.FormatConditionnaly(); //1,000

const double numberWithDecimals = 1000.5;
string result2 = numberWithDecimals.FormatConditionnaly(); //1,000,50

Bit of a hack but you can give this a try:

s = String.Format("{0:N2}", 1000).Replace(".00", "");

Use the "N" format specifier as the format string when you call ToString(); See here

For example:

int intValue = 123456789;
Console.WriteLine(intValue.ToString("N2", 
    CultureInfo.InvariantCulture).Replace(".00", "");

You can customize group sizes etc. as needed.

Why don't you format the values before binding to DevExpress control using plain old C# (Assuming you are doing a bind, as you have not given sufficient details.)

In c# the Math.Round() should do the trick.

Example Math.Round(doubleValue,2) where the second parameter is the number of decimal places.

EDIT:

#,##0.00

I Do not have DevExpress controls to test my solution but I did find http://documentation.devexpress.com/#windowsforms/CustomDocument1498 online (not sure if you see it already).

It seems you can use the Number or Currency masks.

Also take a look at the Zero Placeholder under the custom section. based on the description, '0' is filled where the user has not supplied a value.

example: 123.4 --> 123.40

If the string that you're trying to format is in an XRTableCell of an XtraReport instance, you can handle the BeforePrint event on that cell to format its text. This event is triggered anytime that the report is rendered. Call GetCurrentColumnValue to retrieve the value that you want to format, use any of the code methods from the previous answers that will work for you, and then set that cell's text with your formatted string. Using @dweeberly's answer:

private void OnBeforePrint(object sender, PrintEventArgs e)
{
   object value = this.GetCurrentColumnValue("YourField");
   if (value != null)
   {
       yourCell.Text = String.Format("{0:N2}", value.ToString()).Replace(".00", "");
   }
}