方法一：

在unicode 字符串中，中文的范围是在4E00..9FFF:CJK Unified Ideographs。

通过对字符的unicode编码进行判断来确定字符是否为中文。

程序代码

protected bool   IsChineseLetter(string input,int index)
{
         int code = 0;
         int chfrom = Convert.ToInt32("4e00", 16);     //范围（0x4e00～0x9fff）转换成int（chfrom～chend）
         int chend = Convert.ToInt32("9fff", 16);
         if (input != "")
         {
             code = Char.ConvertToUtf32(input, index);     //获得字符串input中指定索引index处字符unicode编码
            
           if (code >= chfrom && code <= chend)    
             {
                 return true;     //当code在中文范围内返回true

             }
             else
             {
                 return false ;     //当code不在中文范围内返回false
             }
         }
           return false;
}

方法二：

程序代码

<DIV class=UBBPanel><DIV class=UBBContent>
         public bool IsChina(string CString)
           {
               bool BoolValue = false;
               for (int i = 0; i < CString.Length; i++)
               {
                   if (Convert.ToInt32(Convert.ToChar(CString.Substring(i, 1))) < Convert.ToInt32(Convert.ToChar(128)))
                   {
                       BoolValue = false;
                   }
                   else
                   {
                       return BoolValue = true;
                   }
               }
               return BoolValue;
           }</DIV></DIV>

方法三：

程序代码

<DIV class=UBBPanel><DIV class=UBBContent>
         /// <summary>
         /// 判断句子中是否含有中文
         /// </summary>
         /// <param >字符串</param>
         public bool WordsIScn(string words)
         {
             string TmmP;

             for (int i = 0; i < words.Length; i++)
             {
                 TmmP = words.Substring(i, 1);

                 byte[] sarr = System.Text.Encoding.GetEncoding("gb2312").GetBytes(TmmP);

                 if (sarr.Length == 2)
                 {
                     return true;
                 }
             }
             return false;
         }</DIV></DIV>

方法四：

程序代码

<DIV class=UBBPanel><DIV class=UBBContent>
for (int i=0; i<s.length; i++)
{
Regex rx = new Regex("^[\u4e00-\u9fa5]$");
if (rx.IsMatch(s))
// 是
else
// 否
}
正解！
\u4e00-\u9fa5 汉字的范围。
^[\u4e00-\u9fa5]$ 汉字的范围的正则</DIV></DIV>

方法五：

程序代码

<DIV class=UBBPanel><DIV class=UBBContent>
unicodeencoding   unicodeencoding   =   new   unicodeencoding();  
   byte   []   unicodebytearray   =   unicodeencoding.getbytes(   inputstring   );  
   for(   int   i   =   0;   i   <   unicodebytearray.length;   i++   )  
   {  
   i++;  
   //如果是中文字符那么高位不为0  
   if   (   unicodebytearray   !=   0   )  
   {  
   }  
   ……  </DIV></DIV>

方法六：

程序代码

<DIV class=UBBPanel><DIV class=UBBContent>
/// <summary>
         /// 给定一个字符串，判断其是否只包含有汉字
         /// </summary>
         /// <param name="testStr"></param>
         /// <returns></returns>
         public bool IsOnlyContainsChinese(string testStr)
         {
             char[] words = testStr.ToCharArray();
             foreach (char word in words)
             {
                 if ( IsGBCode(word.ToString()) || IsGBKCode(word.ToString()) )   // it is a GB2312 or GBK chinese word
                 {
                     continue;
                 }
                 else
                 {
                     return false;
                 }
             }
             return true;
         }

         /// <summary>
         /// 判断一个word是否为GB2312编码的汉字
         /// </summary>
         /// <param name="word"></param>
         /// <returns></returns>
         private bool IsGBCode(string word)
         {
             byte[] bytes = Encoding.GetEncoding("GB2312").GetBytes(word);
             if (bytes.Length <= 1)   // if there is only one byte, it is ASCII code or other code
             {
                 return false;
             }
             else
             {
                 byte byte1 = bytes[0];
                 byte byte2 = bytes[1];
                 if (byte1 >= 176 && byte1 <= 247 && byte2 >= 160 && byte2 <= 254)     //判断是否是GB2312
                 {
                     return true;
                 }
                 else
                 {
                     return false;
                 }
             }
         }

         /// <summary>
         /// 判断一个word是否为GBK编码的汉字
         /// </summary>
         /// <param name="word"></param>
         /// <returns></returns>
         private bool IsGBKCode(string word)
         {
             byte[] bytes = Encoding.GetEncoding("GBK").GetBytes(word.ToString());
             if (bytes.Length <= 1)   // if there is only one byte, it is ASCII code
             {
                 return false;
             }
             else
             {
                 byte byte1 = bytes[0];
                 byte byte2 = bytes[1];
                 if ( byte1 >= 129 && byte1 <= 254 && byte2 >= 64 && byte2 <= 254)     //判断是否是GBK编码
                 {
                     return true;
                 }
                 else
                 {
                     return false;
                 }
             }
         }



         /// <summary>
         /// 判断一个word是否为Big5编码的汉字
         /// </summary>
         /// <param name="word"></param>
         /// <returns></returns>
         private bool IsBig5Code(string word)
         {
             byte[] bytes = Encoding.GetEncoding("Big5").GetBytes(word.ToString());
             if (bytes.Length <= 1)   // if there is only one byte, it is ASCII code
             {
                 return false;
             }
             else
             {
                 byte byte1 = bytes[0];
                 byte byte2 = bytes[1];
                 if ( (byte1 >= 129 && byte1 <= 254) && ((byte2 >= 64 && byte2 <= 126) || (byte2 >= 161 && byte2 <= 254)) )     //判断是否是Big5编码
                 {
                     return true;
                 }
                 else
                 {
                     return false;
                 }
             }
         }</DIV></DIV>