Preventing Overlapping Events with Advanced Form

[Michael]

I am trying to prevent users from creating overlapping events in our calendar.  I was able to implement this somewhat successfully using the demo at https://demos.telerik.com/aspnet-ajax/scheduler/examples/limitconcurrentappointments/defaultvb.aspx.  I am having an issue though due to the fact that we use a customized Advanced Form template for our events.  On insert or update, I can use the ExceedsLimit() function to cancel the insert or update, but the Advanced Form is cleared out and loses all of the information the user has entered.  Ideally we would present the user with an error message and allow them to fix the data rather than having to enter it all over from scratch.  Is this possible?

I updated the Advanced Insert and Edit Forms demo located at https://demos.telerik.com/aspnet-ajax/scheduler/examples/advancedformtemplate/defaultvb.aspx to demonstrate the issue.

DefaultVB.aspx

<%@ Page Language="vb" AutoEventWireup="true" Inherits="Scheduler.Examples.AdvancedFormTemplate.DefaultVB"
    CodeFile="DefaultVB.aspx.vb" MasterPageFile="~/MasterPageCDNDisabled.master" %>

<%@ Register TagPrefix="sds" Namespace="Telerik.Web.SessionDS" %>
<%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>
<%@ Register TagPrefix="scheduler" TagName="AdvancedForm" Src="AdvancedFormCS.ascx" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">
    <link rel="Stylesheet" type="text/css" href="styles.css" />
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceholder1" runat="Server">
    <telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
        <AjaxSettings>
            <telerik:AjaxSetting AjaxControlID="RadScheduler1">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadScheduler1" LoadingPanelID="RadAjaxLoadingPanel1" />
                </UpdatedControls>
            </telerik:AjaxSetting>
        </AjaxSettings>
    </telerik:RadAjaxManager>
    <telerik:RadAjaxLoadingPanel ID="RadAjaxLoadingPanel1" runat="server" />
    <telerik:RadScriptBlock runat="Server" ID="RadScriptBlock1">
        <script type="text/javascript" src="scripts.js"></script>
    </telerik:RadScriptBlock>
    <telerik:RadNotification runat="server" ID="RadNotification1" Title="Error" TitleIcon="warning" ContentIcon="warning"
        Position="Center" Width="430px" Height="200px" AutoCloseDelay="10000" ShowSound="warning" Font-Size="Large">
        <NotificationMenu Visible="false"></NotificationMenu>
    </telerik:RadNotification>
    <div class="demo-container no-bg">
        <telerik:RadScheduler RenderMode="Lightweight" runat="server" ID="RadScheduler1"
            SelectedDate="2012-04-16"
            OnDataBound="RadScheduler1_DataBound"
            OnAppointmentCreated="RadScheduler1_AppointmentCreated"
            OnAppointmentInsert="RadScheduler1_AppointmentInsert"
            OnAppointmentDataBound="RadScheduler1_AppointmentDataBound"
            OnClientFormCreated="schedulerFormCreated"
            CustomAttributeNames="AppointmentColor"
            EnableDescriptionField="true">
            <AdvancedForm Modal="true" EnableTimeZonesEditing="true" />
            <Reminders Enabled="true" />
            <AppointmentTemplate>
                <div class="rsAptSubject">
                    <%# Eval("Subject") %>
                </div>
                <%# Eval("Description") %>
            </AppointmentTemplate>
            <AdvancedEditTemplate>
                <scheduler:AdvancedForm runat="server" ID="AdvancedEditForm1" Mode="Edit"
                    Subject='<%# Bind("Subject") %>'
                    Description='<%# Bind("Description") %>'
                    Start='<%# Bind("Start") %>'
                    End='<%# Bind("End") %>'
                    RecurrenceRuleText='<%# Bind("RecurrenceRule") %>'
                    Reminder='<%# Bind("Reminder") %>'
                    AppointmentColor='<%# Bind("AppointmentColor") %>'
                    UserID='<%# Bind("User") %>'
                    RoomID='<%# Bind("Room") %>'
                    TimeZoneID='<%# Bind("TimeZoneID") %>' />
            </AdvancedEditTemplate>
            <AdvancedInsertTemplate>
                <scheduler:AdvancedForm runat="server" ID="AdvancedInsertForm1" Mode="Insert"
                    Subject='<%# Bind("Subject") %>'
                    Start='<%# Bind("Start") %>'
                    End='<%# Bind("End") %>'
                    Description='<%# Bind("Description") %>'
                    RecurrenceRuleText='<%# Bind("RecurrenceRule") %>'
                    Reminder='<%# Bind("Reminder") %>'
                    AppointmentColor='<%# Bind("AppointmentColor") %>'
                    UserID='<%# Bind("User") %>'
                    RoomID='<%# Bind("Room") %>'
                    TimeZoneID='<%# Bind("TimeZoneID") %>' />
            </AdvancedInsertTemplate>
            <TimelineView UserSelectable="false" />
            <TimeSlotContextMenuSettings EnableDefault="true" />
            <AppointmentContextMenuSettings EnableDefault="true" />
        </telerik:RadScheduler>
    </div>

</asp:Content>

 

DefaultVB.aspx.vb

Imports System
Imports System.Web.UI
Imports System.Drawing
Imports System.Web.UI.WebControls

Imports Telerik.Web.UI

Namespace Scheduler.Examples.AdvancedFormTemplate
    Public Class DefaultVB
        Inherits System.Web.UI.Page

        Private Const ProviderSessionKey As String = "Telerik.Web.Examples.Scheduler.AdvancedFormTemplate.DefaultVB"

        ' You can safely ignore this method.
        ' Its purpose is to limit the changes to the underlying data only to the active user session.
        Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)

            Dim manager As ScriptManager = RadScriptManager.GetCurrent(Page)
            manager.Scripts.Add(New ScriptReference(ResolveUrl("AdvancedForm.js")))

            Dim provider As XmlSchedulerProvider
            If ((Session(ProviderSessionKey) Is Nothing) _
               OrElse Not IsPostBack) Then
                provider = New XmlSchedulerProvider(Server.MapPath("~/App_Data/Appointments_CustomTemplates.xml"), False)
                Session(ProviderSessionKey) = provider
            Else
                provider = CType(Session(ProviderSessionKey), XmlSchedulerProvider)
            End If
            RadScheduler1.Provider = provider
        End Sub

        Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
            RadScheduler1.TimeZoneID = "Pacific Standard Time"
        End Sub

        Protected Sub RadScheduler1_DataBound(ByVal sender As Object, ByVal e As EventArgs)
            RadScheduler1.ResourceTypes.FindByName("User").AllowMultipleValues = True
            RadScheduler1.ResourceTypes.FindByName("Room").AllowMultipleValues = False
        End Sub

        Protected Sub RadScheduler1_AppointmentCreated(ByVal sender As Object, ByVal e As AppointmentCreatedEventArgs)
            If e.Appointment.RecurrenceState = RecurrenceState.Master OrElse e.Appointment.RecurrenceState = RecurrenceState.Occurrence Then
                Dim recurrenceStateDiv As New Label()
                recurrenceStateDiv.CssClass = "rsAptRecurrence"
                Dim recurrenceStateIcon As New Label()
                recurrenceStateIcon.CssClass = "t-font-icon t-i-recurrence"
                recurrenceStateDiv.Controls.Add(recurrenceStateIcon)
                e.Container.Controls.AddAt(0, recurrenceStateDiv)
            End If
            If e.Appointment.RecurrenceState = RecurrenceState.Exception Then
                Dim recurrenceStateDiv As New Label()
                recurrenceStateDiv.CssClass = "rsAptRecurrenceException"
                Dim recurrenceStateIcon As New Label()
                recurrenceStateIcon.CssClass = "t-font-icon t-i-recurrence-exception"
                recurrenceStateDiv.Controls.Add(recurrenceStateIcon)
                e.Container.Controls.AddAt(0, recurrenceStateDiv)
            End If
        End Sub

        Protected Sub RadScheduler1_AppointmentDataBound(ByVal sender As Object, ByVal e As SchedulerEventArgs)
            Dim colorAttribute As String = e.Appointment.Attributes("AppointmentColor")
            If Not String.IsNullOrEmpty(colorAttribute) Then
                Dim colorValue As Integer
                If Integer.TryParse(colorAttribute, colorValue) Then
                    Dim borderColorValue As Integer = CInt(If(colorValue < -&H7F7F7F, colorValue + &H202020, colorValue - &H202020))
                    e.Appointment.BackColor = Color.FromArgb(colorValue)
                    e.Appointment.BorderColor = Color.FromArgb(borderColorValue)
                End If
            End If
            e.Appointment.ToolTip = e.Appointment.Subject + ": " + e.Appointment.Description
        End Sub

        Protected Sub RadScheduler1_AppointmentInsert(sender As Object, e As SchedulerCancelEventArgs)
            If ExceedsLimit(e.Appointment) Then
                e.Cancel = True
                RadNotification1.Show("Cannot add appointment! There are too many appointments in this time slot. You can only have " & AppointmentsLimit)
            End If
        End Sub

        Private Const AppointmentsLimit As Integer = 1

        Private Function ExceedsLimit(apt As Appointment) As Boolean
            Dim appointmentsCount As Integer = 0
            For Each existingApt As Appointment In RadScheduler1.Appointments.GetAppointmentsInRange(apt.Start, apt.[End])
                If existingApt.Visible Then
                    appointmentsCount += 1
                End If
            Next

            Return (appointmentsCount > AppointmentsLimit - 1)
        End Function
    End Class
End Namespace