应用程序中的server.transfer(“error_404.aspx”)返回空白页

我在global.asx的application_error sub中查找httpexceptions

Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)

        Dim ex As Exception = HttpContext.Current.Server.GetLastError()

        If ex IsNot Nothing Then
            If TypeOf (ex) Is HttpUnhandledException Then
                If ex.InnerException Is Nothing Then
                    Server.Transfer("error.aspx", False)
                End If
                ex = ex.InnerException
            End If

            If TypeOf (ex) Is HttpException Then
                Dim httpCode As Integer = CType(ex, HttpException).GetHttpCode()
                If httpCode = 404 Then
                    Server.ClearError()
                    Server.Transfer("error_404.aspx", False)
                End If
            End If
        End If
End Sub

我可以单步执行此代码并确认它确实命中了server.transfer(“error_.aspx”)以及error_.aspx的页面加载,但它显示的只是一个空白页面。