Remove any trailing commas from comma separated concatenated strings.

TrimTrailingComma.cs

public static string TrimTrailingComma(string value)
{
    if (value.Length >= 2)
    {
        if(value[value.Length-1].Equals(" ") && value[value.Length-2].Equals(","))
        {
            value = value.Substring(0, value.Length - 2);
        }
        else if (value[value.Length - 1].Equals(","))
        {
            value = value.Substring(0, value.Length - 2);
        }
    }
    return value;
}