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

An alternative to the above mentioned responses would be to use

this.lblSearchResults1.Text = String.Format("{0:N}", Convert.ToDouble(lblSearchResults1.Text))

If you wanted decimal places, just enter the amount of decimal places you wish to have after the N. The following example will return the value with 2 decimal places.

this.lblSearchResults1.Text = String.Format("{0:N2}", Convert.ToDouble(lblSearchResults1.Text))

See http://msdn.microsoft.com/en-us/library/system.string.format.aspx for more information.

Answer 2

For complete custom control, use ... .ToString("#,##0.00") or variations thereof. The . and , will be replaced by culture dependent symbols. In most of europe you'd get 1.234,56.
Another useful picture is 0.0#.

To use a pattern depending on the users (or on a selected) culture, use The Numeric ("N") Format Specifier, as in .ToString("N") or "... {0:N}".

Answer 3

If you take a closer look at Standard Numeric Format Strings you can try one of the following:

.ToString("n", CultureInfo.GetCultureInfo("en-US"))
.ToString("n", CultureInfo.GetCultureInfo("de-DE"))
.ToString("n", CultureInfo.CurrentCulture)

Answer 4

Do not cast integral to double to do this!
Use NumberFormatInfo helper class, e.g:

    var nfi = new NumberFormatInfo() {
        NumberDecimalDigits = 0,
        NumberGroupSeparator = "."
    };

    var i = 1234567890;
    var s = i.ToString("N", nfi); // "1.234.567.890"

Answer 5

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

Answer 6

The easiest way to do it would be something like:

Convert.ToDouble("1234567.12345").ToString("N")

If you want to control the decimal places you can do something like:

Convert.ToDouble("1234567.12345").ToString("N3")

In general look at the overloads on ToString for more exciting possibilities.