关于值无法转换问题

[lew830715]

源代码如下
调用代码:
MyTreeDB.TreeBind_ViewDefine(StrViewID, "mainFrame", TreeView1, StrFileName)

其中
StrViewID = Request.QueryString("viewid")
Protected WithEvents TreeView1 As Microsoft.Web.UI.WebControls.TreeView
StrFileName = Server.MapPath(".") + "\ViewFiles\" + StrViewID + "\Mysoft_Attribute.xml"

方法定义:
Public Sub TreeBind_ViewDefine(ByVal strViewID As String, ByVal strFrame As String, ByVal TreeView1 As TreeView, ByVal strFileName As String)
'省略....
End Sub

D:\工作目录\EIP\eip\ViewDefine\ViewDefine_Tree.aspx.vb(34): 类型“Microsoft.Web.UI.WebControls.TreeView”的值无法转换为“Microsoft.Web.UI.WebControls.TreeView”。

大家有没有遇到这样的情况呢,麻烦请哪位帮下哦.
首次发贴.