本文实例讲述了C#按字节数截取字符串并在后面加上省略号...的方法，这是一个自定义的C#函数，函数的使用说明如下：

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

函数代码如下：

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;}

以下所示示例也是根据字节数截取字符串的，只是这个函数后面不加省略号……

/// 按字节数截取字符串(不带省略号)/// </summary>/// <param name="origStr">原始字符串</param>/// <param name="endIndex">提取前endIdex个字节</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;}