How can i get the current selected value of another dropdown list column in GridView basing from one selected DropDownList.

i have two DropDownList columns class and stream.

i wanted to get the value at dropdown list class upon selecting the current value stream.

my code on selected in stream.

Protected Sub ddlstream_SelectedIndexChanged(sender As Object, e As EventArgs)
    Dim dropDownList As DropDownList = CType(sender, DropDownList)
    ' Dim selectedCity As String = DataBinder.Eval(e.Row.DataItem, "City").ToString()
    'Get the ID of the DropDownList.
    Dim k As String
    Dim id As String = dropDownList.SelectedValue
    k = dropDownList.SelectedItem.Text
    ' ClientScript.RegisterClientScriptBlock(Me.GetType(), "alert", "alert('" & dropDownList.SelectedItem.Text & "');", True)
    Dim index As Integer
    Dim ddl As Object = TryCast(Stockbooks.Rows(index).FindControl("lblCountry2"), DropDownList)
    ' Dim text As String = ddl.SelectedItem.Text
    'Dim value As String = ddl.SelectedItem.Value
 
    Dim country As String = TryCast(Stockbooks.SelectedRow.FindControl("lblCountry2"), Label).Text
    Using Conb As New SqlConnection(conString)
        Conb.Open()
        Using cmd As New SqlCommand
            cmd.Connection = Conb
            cmd.CommandType = CommandType.StoredProcedure
            cmd.CommandText = "Controlclasscream"
            cmd.Parameters.Add("@c", SqlDbType.Int).Value = country
            cmd.ExecuteReader()
        End Using
    End Using
End Sub