Error while using label to query database

Private Sub BindGrid()
        Dim constring As String = ConfigurationManager.ConnectionStrings("connstr").ConnectionString
        Using con As New SqlConnection(constring)
            Using cmd As New SqlCommand("SELECT * from [table] WHERE ID=@Label6")
                Using sda As New SqlDataAdapter()
                    cmd.Connection = con
                    cmd.Parameters.Add("@Label6", Label.Text)
                    sda.SelectCommand = cmd
                    Using dt As New DataTable()
                        sda.Fill(dt)
                        GridView2.DataSource = dt
                        GridView2.DataBind()
                    End Using
                End Using
        End Using
    End Using
End Sub

 Public Sub LinkButton1_Click(sender As Object, e As EventArgs)
    Dim Lnk As LinkButton = DirectCast(sender, LinkButton)
    Label6.Text = Lnk.Text
    LinkButton1_ModalPopupExtender.Show()
End Sub

cmd.Parameters.Add("@Label6", SqlDbType.Int)
                   cmd.Parameters.Add("Label6", SqlDbType.Int).Value = Label6.Text
                   cmd.Parameters.Add("@Label6", SqlDbType.Int).Value = Convert.ToInt32(Label6.Text)
                   cmd.Parameters.AddWithValue("@Label6", Convert.ToInt16(Label6.Text))
                   cmd.Parameters.AddWithValue("@Label6", Label6.Text)

<asp:LinkButton ID="lnkDummy" runat="server"></asp:LinkButton>
   <cc1:ModalPopupExtender ID="LinkButton1_ModalPopupExtender" runat="server" Enabled="True" TargetControlID="lnkDummy" PopupControlID="Panel1"> </cc1:ModalPopupExtender>
   <asp:Panel ID="Panel1" runat="server" Height="164px" Width="284px" BackColor="SlateGray" ><br /><br />
         <center><asp:Label ID="Label6" runat="server" Text="Label"></asp:Label><br />
             <asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="false"
       PageSize="2" AllowPaging="true">
                 <Columns>

               <asp:BoundField DataField="Status" HeaderText="Status" SortExpression="Status" />
               <asp:BoundField DataField="Comments" HeaderText="Comments" SortExpression="Comments" />
               <asp:BoundField DataField="Processed_By" HeaderText="Processed_By" SortExpression="Processed_By" />

           </Columns>
             </asp:GridView>
         <asp:Button ID="Button3" runat="server" CssClass="btn btn-default btn-md" Text="Close"/></center>
   </asp:Panel>