我在使用一个通用防注入的类。这个类就是过滤一些关键字，但是我新闻里面如果有这些关键字就会“误杀”。请问有没有办法解决这个问题！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

public class cedar : IHttpModule
{
public void Dispose()
{
throw new NotImplementedException();
}

public void Init(HttpApplication context)
{
context.AcquireRequestState += new EventHandler(application_AcquireRequestState);
}
private void application_AcquireRequestState(object sender, EventArgs e)
{
HttpContext content = ((HttpApplication)sender).Context;
try
{
string sqlErrorPage = "sqlErrorPage.html";//转到默认页面
string keyValue = string.Empty;
string requestUrl = content.Request.Path.ToString();
if (content.Request.QueryString != null)
{
foreach (string val in content.Request.QueryString)
{
keyValue = content.Server.UrlDecode(content.Request.QueryString[val]);
if (!processSqlStr(keyValue))
{
content.Response.Write("<script>alert('请不要提交非法字符')</script>");
content.Response.End();
break;
}
}
}
if (content.Request.Form != null)
{
foreach (string val in content.Request.Form)
{
keyValue = content.Server.HtmlDecode(content.Request.Form[val]);
if (keyValue == "_ViEWSTATE") continue;
if (!processSqlStr(keyValue))
{
content.Response.Write("<script>alert('请不要提交非法字符')</script>");
content.Response.End();
break;
}
}
}
}
catch (Exception ex)
{
}
}

private bool processSqlStr(string str)
{
bool returnValue = true;
try
{
if (str.Trim() != "")
{
//取得webconfig中过滤字符串
// string sqlStr = ConfigurationManager.AppSettings["FilterSql"].Trim();
string sqlStr = "'|declare|exec|varchar|cursor|begin|open|drop|creat|select|truncate|Execute";
string[] sqlStrs = sqlStr.Split('|');
foreach (string ss in sqlStrs)
{
if (str.ToLower().IndexOf(ss) >= 0)
{
sqlStr = ss;
returnValue = false;
break;
}
}
}
}
catch
{
returnValue = false;
}
return returnValue;
}
}