鴨爸的隨手寫寫

這一段程式是好久之前有需要時去找到的

剛好有需要用到的東東所以就記了下來

主要是用System.Globalization.UnicodeCategory(定義字元Unicode分類)

將字串轉成Unicode字元陣列後開始讀取

    protected void Page_Load(object sender, EventArgs e)
    {
        //讀取字串有多少Byte
        //string tByte = "中文chk%%";
        //Response.Write(System.Text.Encoding.Default.GetBytes(tByte).Length);

        //呼叫GetTrim
        string str = "sA中文字Abc字";              
        Response.Write(GetTrim(str,0,5));
    }
        
/// 
/// 依Byte讀取字串
/// 
/// 被讀取的字串
/// 開始位置
/// 讀取多少Byte
/// 回傳字串
    private string GetTrim(string strVal, int sIndex, int length)
    {
        //轉成Unicode字元陣列
        char[] cArray = strVal.ToCharArray();        
        string returnValue = "";        
        int returnLen = 0;
        int index = 0;
        int i = 0;

        while (index < (startIndex + length))
        {
            char ch = cArray[i];
            System.Globalization.UnicodeCategory category = char.GetUnicodeCategory(ch);
            if (category == System.Globalization.UnicodeCategory.OtherLetter)
                index += 2; 
            else 
                index += 1;

            if (index >= (startIndex + 1))
            {
                if (category == System.Globalization.UnicodeCategory.OtherLetter)
                    returnLen += 2;
                else 
                    returnLen += 1;

                if (returnLen <= length) 
                    returnValue += ch.ToString();
            }
            i++;
        } 
        return returnValue;        
    }