The DataSourceID of GridView1 must be the ID of a control of type IDataSource. A control with ID AccessDataSource1 could not be found.

in my asp.net+vb+accessdatabase web. ihave the following code to display data in gridview.

Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
        Dim AccessDataSource1 As New AccessDataSource
        AccessDataSource1.ID = "AccessDataSource1"
        Me.Page.Controls.Add(AccessDataSource1)
        AccessDataSource1.DataFile = System.Configuration.ConfigurationManager.AppSettings("baijuep")
        AccessDataSource1.SelectCommand = "SELECT kNO, name, company from pers where company=?"
        AccessDataSource1.SelectParameters.Add("company ", DropDownList1.SelectedValue)
        GridView1.DataSourceID = "AccessDataSource1"
        GridView1.DataBind()
    End Sub

But it gives error as under

The DataSourceID of 'GridView1' must be the ID of a control of type IDataSource.  A control with ID 'AccessDataSource1' could not be found.