ASP.NET中用过TreeView的过来看看，怎么经常出现这样的错误啊，不能访问“Microsoft.Web.UI.WebControls”

分析器错误信息: 访问被拒绝：“Microsoft.Web.UI.WebControls”。

源错误:


行 196： <add assembly="System.EnterpriseServices, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
行 197： <add assembly="System.Web.Mobile, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
行 198： <add assembly="*"/>
行 199： </assemblies>
行 200： </compilation>


源文件: c:\windows\microsoft.net\framework\v1.1.4322\Config\machine.config 行: 198

程序集加载跟踪: 下列信息有助于确定程序集“Microsoft.Web.UI.WebControls”无法加载的原因。


=== Pre-bind state information ===
LOG: DisplayName = Microsoft.Web.UI.WebControls
(Partial)
LOG: Appbase = file:///D:/项目/web/DocumentMg
LOG: Initial PrivatePath = bin
Calling assembly : (Unknown).
===

LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Post-policy reference: Microsoft.Web.UI.WebControls
LOG: Attempting download of new URL file:///C:/WINDOWS/Microsoft.NET/Framework/v1.1.4322/Temporary ASP.NET Files/documentmg/8fbcca04/b8afa827/Microsoft.Web.UI.WebControls.DLL.
LOG: Attempting download of new URL file:///C:/WINDOWS/Microsoft.NET/Framework/v1.1.4322/Temporary ASP.NET Files/documentmg/8fbcca04/b8afa827/Microsoft.Web.UI.WebControls/Microsoft.Web.UI.WebControls.DLL.
LOG: Attempting download of new URL file:///D:/项目/web/DocumentMg/bin/Microsoft.Web.UI.WebControls.DLL.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Post-policy reference: Microsoft.Web.UI.WebControls, Version=1.0.2.226, Culture=neutral, PublicKeyToken=null