在C#中模擬VB幾個常用的函數

原始文章出自於此


Left(string, int)
// 取得由左數來第N位字串
public static string Left(string sSource, int iLength)
{
    if (sSource.Trim().Length > 0)
        return sSource.Substring(0, iLength > sSource.Length ? sSource.Length : iLength);
    else
        return "";
       
}

Right(string, int)
// 取得由右數來第N位字串
public static string Right(string sSource, int iLength)
{
    if (sSource.Trim().Length > 0)
        return sSource.Substring(iLength > sSource.Length ? 0 : sSource.Length - iLength);
    else
        return "";
}


Mid(string, int, int)
// 取得起始位置至結束之字串
public static string Mid(string sSource, int iStart, int iLength)
{
    if (sSource.Trim().Length > 0)
    {
        int iStartPoint = iStart > sSource.Length ? sSource.Length : iStart;
        return sSource.Substring(iStartPoint, iStartPoint + iLength > sSource.Length ? sSource.Length - iStartPoint : iLength);
    }
    else
        return "";
}



IsNumber(string)
// 判斷是否為數字型態
public static Boolean IsNumber(string sSource)
{
    int flag = 0;
    sSource = sSource.Trim();
    if (sSource != "")
    {
        char[] chars = sSource.ToCharArray();
        for (int i = 0; i < chars.Length; i++)
        {
            if (!char.IsNumber(chars[i]))
            {
                flag++;
            }
        }
    }
    else
        flag = 1;
    if (flag > 0)
    {
        return false;
    }
    else
    {
        return true;
    }
}


IsDate(string)
// 檢查是否為日期格式,驗證格式(YYYY/MM/DD,YYYYMMDD,YYY/MM/DD,YYYMMDD)
public static Boolean IsDate(string myDate)
{
    Boolean flag = true;
    //檢查是否空字串
    myDate = myDate.Trim();
    if (myDate == "")
        return false;
    //檢查是否為數字格式
    if (IsNumber(myDate.Replace("/","")) == true)
    {
        int Dlg = myDate.Length;
        switch (Dlg)
        {
            case 7:
                //民國年 YYYMMDD
                try
                {
                    int tmpY = Convert.ToInt32(Left(myDate, 3)) + 1911;
                    string tmpDate = tmpY + Right(myDate, 4);
                    DateTime dt = DateTime.ParseExact(tmpDate, "yyyyMMdd", null, System.Globalization.DateTimeStyles.AllowWhiteSpaces);
                }
                catch { flag = false; }
                break;
            case 8:
                //西元年 YYYYMMDD
                try
                {
                    DateTime dt = DateTime.ParseExact(myDate, "yyyyMMdd", null, System.Globalization.DateTimeStyles.AllowWhiteSpaces);
                }
                catch { flag = false; }
                break;
            case 9:
                //民國年 YYY/MM/DD
                try
                {
                    string tmpStr = myDate.Replace("/", "");
                    int tmpY = Convert.ToInt32(Left(tmpStr, 3)) + 1911;
                    string tmpDate = tmpY + Right(tmpStr, 4);
                    DateTime dt = DateTime.ParseExact(tmpDate, "yyyyMMdd", null, System.Globalization.DateTimeStyles.AllowWhiteSpaces);
                }
                catch { flag = false; }
                break;
            case 10:
                //西元年 YYYY/MM/DD
                if (myDate.IndexOf("/") == 4 || myDate.LastIndexOf("/") == 7)
                {
                    try
                    {
                        DateTime dt = DateTime.Parse(myDate);
                    }
                    catch { flag = false; }
                }
                else { flag = false; }
                break;
            default:
                flag = false;
                break;
        }
    }
    else
    {
        flag = false;
    }
    return flag;
}


Asc(string)
// 取得字元對應的ASCII碼
public static int Asc(string character)
{
    if (character.Trim().Length == 1)
    {
        System.Text.ASCIIEncoding asciiEncoding = new System.Text.ASCIIEncoding();
        int intAsciiCode = (int)asciiEncoding.GetBytes(character)[0];
        return (intAsciiCode);
    }
    else
    {
        throw new ApplicationException("Character is not valid.");
    }
}

Chr(int)
// 取得ASCII碼對應字元
public static string Chr(int asciiCode)
 {
     if (asciiCode >= 0 && asciiCode <= 255)
     {
         System.Text.ASCIIEncoding asciiEncoding = new System.Text.ASCIIEncoding();
         byte[] byteArray = new byte[] { (byte)asciiCode };
         string strCharacter = asciiEncoding.GetString(byteArray);
         return (strCharacter);
     }
     else
     {
         throw new ApplicationException("ASCII Code is not valid.");
     }
 }