可以用來判斷用戶是否輸入錯數值！

/// <summary>
/// 判斷是否為數字
/// </summary>
public static bool IsNumeric(object obj)
{
    double retNum;
    bool Result = Double.TryParse(obj.ToString(), System.Globalization.NumberStyles.Any
                        , System.Globalization.NumberFormatInfo.InvariantInfo, out retNum);

    return Result;
}