ToSpecificCurrencyString

/// <summary>
/// Extensions for numeric types.
/// </summary>
public static class NumericExtensions
{
 /// <summary>
 /// Format a double using specific culture currency settings.
 /// </summary>
 /// <param name="value">The double to be formatted.</param>
 /// <param name="cultureName">The string representation for the culture to be used, for instance "en-US" for US English.</param>
 /// <returns>The double formatted based on specific culture currency settings.</returns>
 public static string ToSpecificCurrencyString(this double value, string cultureName)
 {
 CultureInfo currentCulture = new CultureInfo(cultureName);
 return (string.Format(currentCulture, "{0:C}", value));
 }
}

double test = 120.45;
string testString = test.ToSpecificCurrencyString("en-US");