WebApp_Vb.net ถามปัญหาเรื่อง ObjectDataSource เกิดการ Error = The type specified in the TypeName property of ObjectDataSource 'ObjectDataSource1' could not be found.

<%@ Page Title="" Language="VB" MasterPageFile="~/MasterPage01.master" AutoEventWireup="false" CodeFile="Testt.aspx.vb" Inherits="Testt" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>


<%@ Register src="UserControl/UCGridPager/UCGridPager.ascx" tagname="UCGridPager" tagprefix="uc1" %>


<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
   <asp:GridView ID="GridView1" runat="server" AllowPaging="True" CssClass="mGrid" PagerStyle-CssClass="pgr"
            AlternatingRowStyle-CssClass="alt" GridLines="None" AutoGenerateColumns="False"
            DataSourceID="ObjectDataSource1" ShowHeaderWhenEmpty="True" 
            AllowSorting="True">
            <AlternatingRowStyle CssClass="alt" />
            <Columns>
                <asp:CommandField ShowSelectButton="True" />
                <asp:BoundField DataField="EmpID" HeaderText="EmpID" SortExpression="EmpID"  />
                <asp:BoundField DataField="EmployeeName" HeaderText="EmployeeName" SortExpression="EmployeeName" />
                <asp:BoundField DataField="EmployeeAddr" HeaderText="EmployeeAddr" SortExpression="EmployeeAddr" />
            </Columns>
            <PagerSettings Position="Top" />
            <PagerStyle CssClass="pgr" />
            
        </asp:GridView>
        
        <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetDataTest"
            TypeName="Testt" ></asp:ObjectDataSource>

</asp:Content>

Imports System.Data


Partial Class Testt
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then
            CheckCanSave()
        End If
        CheckCanSave()
    End Sub
    Protected Sub CheckCanSave()
        If (GridView1.Rows.Count > 0) Then
            If GridView1.TopPagerRow Is Nothing Then
                GridView1.TopPagerRow.Visible = True
            End If
            If GridView1.BottomPagerRow Is Nothing Then
                GridView1.BottomPagerRow.Visible = True
            End If
        End If
    End Sub

    Public Function GetDataTest() As DataTable
        Dim dTable = New DataTable
        dTable.Columns.Add("EmpID", GetType(Integer))
        dTable.Columns.Add("EmployeeName", GetType(String))
        dTable.Columns.Add("EmployeeAddr", GetType(String))


        For index As Integer = 1 To 1200
            dTable.Rows.Add(index, "Name" & index, "Address" & index)
        Next

        Return dTable
    End Function
End Class