對於會員註冊或是資料填寫的時候，一定會用到的身份證字號驗證公式，提供給有需要的朋友。

首先我們要知道身份證字號的驗證方式為何【身份證字號規則】

但是我相信很多人不想研究...所以整段Code又出現啦

public string IDChk(string vid)
{
    List<string> FirstEng = new List<string> { "A", "B", "C", "D", "E", "F", "G", "H", "J", "K", "L", "M", "N", "P", "Q", "R", "S", "T", "U", "V", "X", "Y", "W", "Z", "I", "O" };
    string aa = vid.ToUpper();
    bool chackFirstEnd = false;
    if (aa.Trim().Length == 10)
    {
        byte firstNo = Convert.ToByte(aa.Trim().Substring(1, 1));
        if (firstNo > 2 || firstNo < 1)
        {
            return "2";
        }
        else
        {
            int x;
            for (x = 0; x < FirstEng.Count; x++)
            {
                if (aa.Substring(0, 1) == FirstEng[x])
                {
                    aa = string.Format("{0}{1}", x + 10, aa.Substring(1, 9));
                    chackFirstEnd = true;
                    break;
                }
 
            }
            if (!chackFirstEnd)
                return "3";
 
            int i = 1;
            int ss = int.Parse(aa.Substring(0, 1));
            while (aa.Length > i)
            {
                ss = ss + (int.Parse(aa.Substring(i, 1)) * (10 - i));
                i++;
            }
            aa = ss.ToString();
            if (vid.Substring(9, 1) == "0")
            {
                if (aa.Substring(aa.Length - 1, 1) == "0")
                {
                    return "0";
                }
                else
                {
                    return "4";
                }
            }
            else
            {
                if (vid.Substring(9, 1) == (10 - int.Parse(aa.Substring(aa.Length - 1, 1))).ToString())
                {
 
                    return "0";
                }
                else
                {
                    return "4";
                }
            }
        }
    }
    else
    {
 
        return "1";
    }
}
//回傳1 代表字數不到10  
//回傳2代表第二碼非1,2  
//回傳3 代表首碼有誤  
//回傳4代表檢查碼不對  

把它寫成一個方法、類別都可以很方便的應用，如果有錯誤還請利用回報告知呢