C#完成依據字節數截取字符串並加上省略號的辦法

C#完成依據字節數截取字符串並加上省略號的辦法。本站提示廣大學習愛好者：（C#完成依據字節數截取字符串並加上省略號的辦法）文章只能為提供參考，不一定能成為您想要的結果。以下是C#完成依據字節數截取字符串並加上省略號的辦法正文

本文實例講述了C#按字節數截取字符串並在前面加上省略號...的辦法，這是一個自界說的C#函數，函數的應用解釋以下：

<param name="origStr">原始字符串</param>
<param name="endIndex">提取前endIdex個字節</param>
<returns></returns>

函數代碼以下：

public static string GetSubString(string origStr, int endIndex)
{
  if (origStr == null || origStr.Length == 0 || endIndex < 0)
    return "";
  int bytesCount = System.Text.Encoding.GetEncoding("gb2312").GetByteCount(origStr);
  if (bytesCount > endIndex)
  {
    int readyLength = 0;
    int byteLength;
    for (int i = 0; i < origStr.Length; i++)
    {
      byteLength = System.Text.Encoding.GetEncoding("gb2312").GetByteCount(new char[] { origStr[i] });
      readyLength += byteLength;
      if (readyLength == endIndex)
      {
        origStr = origStr.Substring(0, i + 1) + "...";
        break;
      }
      else if (readyLength > endIndex)
      {
        origStr = origStr.Substring(0, i) + "...";
        break;
      }
    }
  }
  return origStr;
}

以下所示示例也是依據字節數截取字符串的，只是這個函數前面不加省略號……

/// 按字節數截取字符串(不帶省略號)
/// </summary>
/// <param name="origStr">原始字符串</param>
/// <param name="endIndex">提取前endIdex個字節</param>
/// <returns></returns>
public static string GetSub1String(string origStr, int endIndex)
{
  if (origStr == null || origStr.Length == 0 || endIndex < 0)
    return "";
  int bytesCount = System.Text.Encoding.GetEncoding("gb2312").GetByteCount(origStr);
  if (bytesCount > endIndex)
  {
    int readyLength = 0;
    int byteLength;
    for (int i = 0; i < origStr.Length; i++)
    {
      byteLength = System.Text.Encoding.GetEncoding("gb2312").GetByteCount(new char[] { origStr[i] });
      readyLength += byteLength;
      if (readyLength == endIndex)
      {
        origStr = origStr.Substring(0, i + 1);
        break;
      }
      else if (readyLength > endIndex)
      {
        origStr = origStr.Substring(0, i);
        break;
      }
    }
  }
  return origStr;
}