มีปัญหาเกี่ยวกับการจองเวลาค่ะ ไม่ทราบว่าจะแก้ไขอย่างไร ขอช่วยพี่ๆดูให้หน่อยค่ะ

 Protected Sub cmdSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmdSave.Click
        Dim ds As New DataSet
        Dim check As String
        check = Right(Str(Val(Format(CalendarPopup1.SelectedDate, "yyyy")) - 543), 2) & Format(CalendarPopup1.SelectedDate, "-MM-dd")
        ds = selectData.checkTime(ddlTeachername.SelectedValue, check, TimePicker1.PostedTime.ToString)
        
        Dim runID As Integer
        runID = insertData.runID("Appointment", "Appointment_ID")
        hidApp_ID.Value = runID


        If ds.Tables(0).Rows.Count = 0 Then
            If txtTitle.Text = False & txtContent.Text = False Then
                ScriptManager.RegisterStartupScript(Page, Page.GetType(), "", "alert('" + "กรุณาใส่ข้อมูลให้ครบถ้วน" + "');", True)
            Else
                hidApp_ID.Value = runID
                insertData.insertAppointment(lblStudent_ID.Text, lblStudent_Name.Text, ddlTeachername.SelectedValue, hidApp_ID.Value, txtTitle.Text, CalendarPopup1.SelectedDate, TimePicker1.PostedTime.ToString, txtContent.Text)
                ScriptManager.RegisterStartupScript(Page, Page.GetType(), "", "alert('" + "บันทึกข้อมูลเรียบร้อยแล้ว" + "');", True)
                Response.Redirect("showAppointment_Student.aspx")
                txtTitle.Text = ""
                txtContent.Text = ""
            End If
        Else
            ScriptManager.RegisterStartupScript(Page, Page.GetType(), "", "alert('" + "กรุณาจองเวลาการนัดพบใหม่" + "');", True)
        End If

    End Sub