不知道怎么改错，大家帮我看下
Server Error in '/Oi ' Application.
--------------------------------------------

Compilation Error
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.

Compiler Error Message: CS0104: 'TreeNode ' is an ambiguous reference between 'System.Web.UI.WebControls.TreeNode ' and 'Microsoft.Web.UI.WebControls.TreeNode '

Source Error:



Line 71:
Line 72: }
Line 73: private void CreateDataSource (string Parentid, ref TreeNode Pnode)
Line 74: {
Line 75: string sqlstr = " select distinct m.id, m.ModuleID,m.modulename,m.menupath,m.parentmoduleid ";


Source File: c:\Inetpub\wwwroot\OI\Manage\Tree.aspx.cs Line: 73

[解决办法]
ref 传的参数需要给变量赋值，你应该没有给变量赋值。
如
int i = 1;
int add(ref i)
{
}