/// <summary>
/// 過濾不安全的字符串
/// </summary>
/// <param name="Str"></param>
/// <returns></returns>
public static string FilteSQLStr(string Str)
{
  Str = Str.Replace("'", "");
  Str = Str.Replace("\"", "");
  Str = Str.Replace("&", "&");
  Str = Str.Replace("<", "<");
  Str = Str.Replace(">", ">");
  Str = Str.Replace("delete", "");
  Str = Str.Replace("update", "");
  Str = Str.Replace("insert", "");
  return Str; 
}

#region 過濾 Sql 語句字符串中的注入腳本
/// <summary>
/// 過濾 Sql 語句字符串中的注入腳本
/// </summary>
/// <param name="source">傳入的字符串</param>
/// <returns>過濾后的字符串</returns>
public static string SqlFilter(string source)
{
 //單引號替換成兩個單引號
 source = source.Replace("'", "''");
 //半角封號替換為全角封號，防止多語句執(zhí)行
 source = source.Replace(";", "；");
 //半角括號替換為全角括號
 source = source.Replace("(", "（");
 source = source.Replace(")", "）");
 ///////////////要用正則表達式替換，防止字母大小寫得情況////////////////////
 //去除執(zhí)行存儲過程的命令關(guān)鍵字
 source = source.Replace("Exec", "");
 source = source.Replace("Execute", "");
 //去除系統(tǒng)存儲過程或擴展存儲過程關(guān)鍵字
 source = source.Replace("xp_", "x p_");
 source = source.Replace("sp_", "s p_");
 //防止16進制注入
 source = source.Replace("0x", "0 x");
 return source;
}
#endregion

/// 過濾SQL字符。
/// </summary>
/// <param name="str">要過濾SQL字符的字符串。</param>
/// <returns>已過濾掉SQL字符的字符串。</returns>
public static string ReplaceSQLChar(string str)
{
 if (str == String.Empty)
  return String.Empty; str = str.Replace("'", "‘");
 str = str.Replace(";", "；");
 str = str.Replace(",", ",");
 str = str.Replace("?", "?");
 str = str.Replace("<", "＜");
 str = str.Replace(">", "＞");
 str = str.Replace("(", "(");
 str = str.Replace(")", ")");
 str = str.Replace("@", "＠");
 str = str.Replace("=", "＝");
 str = str.Replace("+", "＋");
 str = str.Replace("*", "＊");
 str = str.Replace("&", "＆");
 str = str.Replace("#", "＃");
 str = str.Replace("%", "％");
 str = str.Replace("$", "￥");
 return str;
}

/// <summary>
/// 過濾標記
/// </summary>
/// <param name="NoHTML">包括HTML，腳本，數(shù)據(jù)庫關(guān)鍵字，特殊字符的源碼 </param>
/// <returns>已經(jīng)去除標記后的文字</returns>
public string NoHtml(string Htmlstring)
{
 if (Htmlstring == null)
 {
  return "";
 }
 else
 {
  //刪除腳本
   Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "", RegexOptions.IgnoreCase);
  //刪除HTML
  Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"([\r\n])[\s]+", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "\"", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", " ", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "\xa1", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "\xa2", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "\xa3", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "\xa9", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, @"&#(\d+);", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);
  //刪除與數(shù)據(jù)庫相關(guān)的詞
  Htmlstring = Regex.Replace(Htmlstring, "select", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "insert", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "delete from", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "count''", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "drop table", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "truncate", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "asc", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "mid", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "char", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "exec master", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "net localgroup administrators", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "and", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "net user", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "or", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "net", "", RegexOptions.IgnoreCase);
  //Htmlstring = Regex.Replace(Htmlstring, "*", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "-", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "delete", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "drop", "", RegexOptions.IgnoreCase);
  Htmlstring = Regex.Replace(Htmlstring, "script", "", RegexOptions.IgnoreCase);
  //特殊的字符
   Htmlstring = Htmlstring.Replace("<", "");
  Htmlstring = Htmlstring.Replace(">", "");
  Htmlstring = Htmlstring.Replace("*", "");
  Htmlstring = Htmlstring.Replace("-", "");
  Htmlstring = Htmlstring.Replace("?", "");
  Htmlstring = Htmlstring.Replace("'", "''");
  Htmlstring = Htmlstring.Replace(",", "");
  Htmlstring = Htmlstring.Replace("/", "");
  Htmlstring = Htmlstring.Replace(";", "");
  Htmlstring = Htmlstring.Replace("*/", "");
  Htmlstring = Htmlstring.Replace("\r\n", "");
  Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();
  return Htmlstring;
 }
}

public static bool CheckBadWord(string str)
{
string pattern = @"select|insert|delete|from|count\(|drop table|update|truncate|asc\(|mid\(|char\(|xp_cmdshell|exec master|netlocalgroup administrators|net user|or|and";
if (Regex.IsMatch(str, pattern, RegexOptions.IgnoreCase))
return true;
return false;
}
public static string Filter(string str)
{
string[] pattern ={ "select", "insert", "delete", "from", "count\\(", "drop table", "update", "truncate", "asc\\(", "mid\\(", "char\\(", "xp_cmdshell", "exec master", "netlocalgroup administrators", "net user", "or", "and" };
for (int i = 0; i < pattern.Length; i++)
{
str = str.Replace(pattern[i].ToString(), "");
}
return str;
}