【转】 如何在后台（c#）判断计算结果x是否为整数！！

不要用異常，用正則表達式。 
/// <summary> 
/// 非負數字。 
/// </summary> 
public const string ZZValidNumeric1=@"^\d+[.]?\d*$"; 
/// <summary> 
/// 數字。 
/// </summary> 
public const string ZZValidNumeric2=@"^[-]?\d+[.]?\d*$"; 
/// <summary> 
/// 非負整數。 
/// </summary> 
public const string ZZValidInt1=@"^\d+$"; 
/// <summary> 
/// 整數。 
/// </summary> 
public const string ZZValidInt2=@"^-?\d+$"; 
/// <summary> 
/// 負整數。 
/// </summary> 
public const string ZZValidInt3=@"^-[0-9]*[1-9][0-9]*$"; 
/// <summary> 
/// 正整數。 
/// </summary> 
public const string ZZValidInt4=@"^[0-9]*[1-9][0-9]*$"; 
/// <summary> 
/// 非正整數。 
/// </summary> 
public const string ZZValidInt5=@"^((-\d+)|(0+))$"; 
/// <summary> 
/// 正則表達式驗證。 
/// </summary> 
/// <param name="str">預檢查的字符串。</param> 
/// <param name="ZZValidItem">正則表達式字符串。</param> 
/// <returns>true:符合格式;false:不符合格式。</returns> 
public static bool IsValidString(string str,string ZZValidItem) 
{ 
return Regex.IsMatch(str,ZZValidItem);              //  使用 Regex.IsMatch 要 引入命名空间：  System.Text.RegularExpressions