asp.net2.0 URL重写以及urlMappings问题(1)

using System;
using System.Web;

public class ReWriteModule : IHttpModule
{
public ReWriteModule()
{
}
public override string ToString()
{
return this.GetType().ToString();
}

void IHttpModule.Dispose()
{
}
private static System.Xml.XmlDocument ruleDoc = null;
private static System.Xml.XmlDocument GetRuleConfig(System.Web.HttpContext app)
{
if (ruleDoc == null)
{
ruleDoc = new System.Xml.XmlDocument();
ruleDoc.Load(app.Server.MapPath("~/rule.xml"));
}
return ruleDoc;
}
public static string GetUrl(System.Web.HttpContext cxt, string path)
{
System.Xml.XmlDocument doc = GetRuleConfig(cxt);
System.Xml.XmlNodeList lst = doc.GetElementsByTagName("RewriterRule");
string pat = "";
foreach (System.Xml.XmlNode nd in lst)
{
System.Xml.XmlNodeList sub = nd.ChildNodes[0].ChildNodes;
foreach (System.Xml.XmlNode chk in sub)
{
pat = "^" chk.InnerText "$";
System.Text.RegularExpressions.Regex reg = new System.Text.RegularExpressions.Regex(pat, System.Text.RegularExpressions.RegexOptions.Compiled | System.Text.RegularExpressions.RegexOptions.IgnoreCase);
if (reg.IsMatch(path))
{
return reg.Replace(path, nd.ChildNodes[1].InnerText);
}
}
}
return null;
}