Message Alert

How do i desplay a message with Ok and Cancel in a datagrid view click button

 Protected Sub grvCarBooking_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles grvCarBooking.RowCommand
        If e.CommandName = "Closed" Then
            Dim Index As Integer = e.CommandArgument
            lblBkID.Text = grvCarBooking.Rows(Index).Cells(0).Text

            '***I NEED ADD THE MESSAGE BOX HERE            

Try
                'Get Car Booking                 Dim SQL As String
                OpenCon()
                SQL = "SELECT * FROM viwBookings WHERE ID=?"
                Dim DR As OleDb.OleDbDataReader
                Dim CMD As New OleDb.OleDbCommand(SQL, OleDbCon)
                CMD.Parameters.AddWithValue("@P1", lblBkID.Text)
                DR = CMD.ExecuteReader(System.Data.CommandBehavior.CloseConnection)
                DR.Read()                txtCarID.Text = DR("CarID")
                txtCarPlateNumber.Text = DR("PlateNumber")
                txtBookID.Text = DR("RqID")
                txtRequesterName.Text = DR("RequesterName")
                txtDriverID.Text = DR("DriverID")
                txtDriverName.Text = DR("DriversName")
                txtKMStart.Text = ""                txtKMEnd.Text = ""
                DR.Close()                CMD.Dispose()
                CloseCon()            Catch ex As Exception           

 End Try
        End If        

If e.CommandName = "Delete" Then
            Dim Index As Integer = e.CommandArgument
            lblBkID.Text = grvCarBooking.Rows(Index).Cells(0).Text
            

'***I NEED ADD THE MESSAGE BOX HERE            

Try  

'Get Car Booking                 Dim SQL As String
                OpenCon()
                SQL = "SELECT * FROM viwBookings WHERE ID=?"
                Dim DR As OleDb.OleDbDataReader
                Dim CMD As New OleDb.OleDbCommand(SQL, OleDbCon)
                CMD.Parameters.AddWithValue("@P1", lblBkID.Text)
                DR = CMD.ExecuteReader(System.Data.CommandBehavior.CloseConnection)
                DR.Read()                txtCarID.Text = DR("CarID")
                txtCarPlateNumber.Text = DR("PlateNumber")
                txtBookID.Text = DR("RqID")
                txtRequesterName.Text = DR("RequesterName")
                txtDriverID.Text = DR("DriverID")
                txtDriverName.Text = DR("DriversName")
                txtKMStart.Text = ""                txtKMEnd.Text = ""
                DR.Close()                CMD.Dispose()
                CloseCon()            Catch ex As Exception           

 End Try
        End If    End Sub