楼主提供的链接打开怎么是这样：
Server Error in '/' Application.
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
Line 565:public string filter(string obj){
Line 566:
Line 567:obj =obj.Replace("'","''");
Line 568:obj =obj.Replace("%","");
Line 569:obj =obj.Replace(";","");
Source File: d:\mobile\tree\ajax\_top2.cs Line: 567
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
ASP.stree_content_aspx.filter(String obj) in d:\mobile\tree\ajax\_top2.cs:567
ASP.stree_content_aspx.Page_Load(Object src, EventArgs e) in d:\mobile\tree\stree\content.aspx:17
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +34
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +47
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1061
Version Information: Microsoft .NET Framework Version:2.0.50727.42; ASP.NET Version:2.0.50727.42
