Error: $get("TargetSlotHiddenField") is null

[Farshad heidary]

hi guys and support team.
i response this error when i drag drop task into schaduler.(dargDrop Schaduler)
what  my problem?
how i can fix it?

tnx

[Farshad heidary]

i test "<%= TargetSlotHiddenField.ClientID %>" but i recive this error:
Error: Sys.WebForms.PageRequestManagerServerErrorException: Object reference not set to an instance of an object.
Source File: http://localhost/IFarshadDotIR/ScriptResource.axd?d=klIR8V_JJaMWoZwdawncxFo8WLDFm0CB58kHqNTypAzeKI61YqJmF171GvgmP2EBFlInwpilgTVeu04xyGMD6tn9twhhV-_C_wBL3PaAZfY1&t=634321714550625000
Line: 5

[Vesko]

Do you have a hidden field called TargetSlotHiddenField on your page like in the demo?

[Nick]

I have the <input type="hidden" runat="server" if="TargetSlotHiddenField"/> in my usercontrol and I still get this error

The drag and drop does not insert it when dropped in the calendar above

    <telerik:RadScriptBlock ID="RadScriptBlock1" runat="server">
        <script type="text/javascript">


            function rowDropping(sender, eventArgs) {
                // Fired when the user drops a grid row
                var htmlElement = eventArgs.get_destinationHtmlElement();
                var scheduler = $find('<%= RadScheduler1.ClientID %>');

                if (isPartOfSchedulerAppointmentArea(htmlElement)) {
                    // The row was dropped over the scheduler appointment area
                    // Find the exact time slot and save its unique index in the hidden field
                    var timeSlot = scheduler._activeModel.getTimeSlotFromDomElement(htmlElement);

                    $get("TargetSlotHiddenField").value = timeSlot.get_index();

                    // The HTML needs to be set in order for the postback to execute normally
                    eventArgs.set_destinationHtmlElement("TargetSlotHiddenField");
                }
                else {
                    // The node was dropped elsewhere on the document
                    eventArgs.set_cancel(true);
                }
            }

            function isPartOfSchedulerAppointmentArea(htmlElement) {
                // Determines if an html element is part of the scheduler appointment area
                // This can be either the rsContent or the rsAllDay div (in day and week view)
                return $telerik.$(htmlElement).parents().is("div.rsAllDay") ||
                            $telerik.$(htmlElement).parents().is("div.rsContent")
            }

            function onRowDoubleClick(sender, args) {
                sender.get_masterTableView().editItem(args.get_itemIndexHierarchical());
            }
        </script>
    </telerik:RadScriptBlock>

    <input type="hidden" runat="server" id="TargetSlotHiddenField" />

    <telerik:RadAjaxManager runat="server" ID="RadAjaxManager1">
        <AjaxSettings>
            <telerik:AjaxSetting AjaxControlID="RadScheduler1">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadScheduler1" />
                </UpdatedControls>
            </telerik:AjaxSetting>
            <telerik:AjaxSetting AjaxControlID="RadGrid1">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadGrid1" />
                </UpdatedControls>
            </telerik:AjaxSetting>
        </AjaxSettings>
    </telerik:RadAjaxManager>
    <telerik:RadSplitter runat="server" ID="RadSplitter1" Height="552px" Width="880px"
        CssClass="exampleContainer" Orientation="Horizontal" Skin="Office2007">
        <telerik:RadPane runat="server" ID="TopPane" Height="400px" Scrolling="None">
            <telerik:RadScheduler ID="RadScheduler1" runat="server" Width="100%" DataSourceID="SchedulerDataSource"
                DataKeyField="AppointmentID" DataStartField="Start" DataEndField="End" DataSubjectField="Subject"
                OnAppointmentCommand="RadScheduler1_AppointmentCommand" Skin="Office2007" Height="100%"
                ShowFooter="false" RowHeaderWidth="52" CustomAttributeNames="Due, Priority" OverflowBehavior="Scroll">
                <AdvancedForm Modal="true" />
                <AppointmentTemplate>
                    <%# Eval("Subject") %>
                    <asp:Button runat="server" ID="UnscheduleAppointment" CssClass="simpleButton" CommandName="Unschedule"
                        Text="&nbsp;" ToolTip="Unschedule this appointment" />
                </AppointmentTemplate>
                <TimeSlotContextMenuSettings EnableDefault="true" />
                <AppointmentContextMenuSettings EnableDefault="true" />
            </telerik:RadScheduler>
        </telerik:RadPane>
        <telerik:RadSplitBar runat="Server" ID="RadSplitBar1" />
        <telerik:RadPane runat="server" ID="BottomPane">
            <div style="float: left; height: 100%; width: 55px; background: #E3EFFF; text-align: center;
                border-right: 1px solid #6593CF;">
                <img src="../images/tasks.gif" alt="" /></div>
            <div style="margin-left: 56px; border: none;">
                <telerik:RadGrid runat="server" ID="RadGrid1" DataSourceID="GridDataSource" GridLines="None"
                    AutoGenerateColumns="False" OnRowDrop="RadGrid1_RowDrop" Skin="Office2007" Style="border: none;
                    outline: 0" Height="100%" AllowAutomaticInserts="True" AllowAutomaticUpdates="true"
                    ShowFooter="true" OnItemCreated="RadGrid1_ItemCreated" OnItemCommand="RadGrid1_ItemCommand"
                    AllowSorting="true">
                    <ClientSettings AllowRowsDragDrop="True">
                        <Selecting AllowRowSelect="True" />
                        <ClientEvents OnRowDropping="rowDropping" OnRowDblClick="onRowDoubleClick" />
                    </ClientSettings>
                    <MasterTableView DataKeyNames="AppointmentID" InsertItemDisplay="Bottom" EditMode="InPlace">
                        <SortExpressions>
                            <telerik:GridSortExpression FieldName="Due" SortOrder="Ascending" />
                        </SortExpressions>
                        <Columns>
                            <telerik:GridTemplateColumn DataField="Subject" HeaderText="Task">
                                <ItemTemplate>
                                    <asp:Label runat="server" ID="Label1" Text='<%# Bind("Subject") %>'></asp:Label>
                                </ItemTemplate>
                                <FooterTemplate>
                                    <asp:LinkButton Text="Add new task" CommandName="<%# RadGrid.InitInsertCommandName %>"
                                        runat="server" ID="LinkButton1"></asp:LinkButton>
                                </FooterTemplate>
                                <EditItemTemplate>
                                    <asp:TextBox runat="Server" ID="TextBox1" Text='<%# Bind("Subject") %>' Width="100%"></asp:TextBox>
                                </EditItemTemplate>
                            </telerik:GridTemplateColumn>
                            <telerik:GridDateTimeColumn DataField="Due" HeaderText="Due Date" DataFormatString="{0:d}"
                                HeaderStyle-Width="200px">
                            </telerik:GridDateTimeColumn>
                            <telerik:GridTemplateColumn DataField="Priority" HeaderText="Priority" HeaderStyle-Width="200px">
                                <ItemTemplate>
                                    <asp:Label runat="Server" ID="Label2" Text='<%#Bind("Priority") %>'></asp:Label>
                                </ItemTemplate>
                                <EditItemTemplate>
                                    <telerik:RadComboBox runat="server" ID="priorityComboBox" SelectedValue='<%#Bind("Priority") %>'
                                        Skin="Office2007" Width="80px">
                                        <Items>
                                            <telerik:RadComboBoxItem Text="High" Value="High" />
                                            <telerik:RadComboBoxItem Text="Medium" Value="Medium" />
                                            <telerik:RadComboBoxItem Text="Low" Value="Low" />
                                        </Items>
                                    </telerik:RadComboBox>
                                    <asp:LinkButton ID="btnUpdate" Text="Save" runat="server" CommandName='<%# IIf(TypeOf Container Is GridDataInsertItem, RadGrid.PerformInsertCommandName, RadGrid.UpdateCommandName) %>'></asp:LinkButton>
                                    <asp:LinkButton ID="btnCancel" Text="Cancel" runat="server" CommandName='<%# RadGrid.CancelCommandName %>'></asp:LinkButton>
                                </EditItemTemplate>
                            </telerik:GridTemplateColumn>
                        </Columns>
                    </MasterTableView>
                </telerik:RadGrid>
            </div>
        </telerik:RadPane>
    </telerik:RadSplitter>

<asp:SqlDataSource ID="SchedulerDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:portal %>"
    SelectCommand="SELECT [AppointmentID], [Start], [End], [Subject], [Due], [Priority]  FROM [Appointments] WHERE ([Start] IS NOT NULL) AND ([End] IS NOT NULL)"
    InsertCommand="INSERT INTO [Appointments] ([Subject], [Start], [End]) VALUES (@Subject, @Start, @End)"
    UpdateCommand="UPDATE [Appointments] SET [Start] = @Start, [End] = @End, [Subject] = @Subject WHERE AppointmentID = @AppointmentID"
    DeleteCommand="DELETE FROM [Appointments] WHERE [AppointmentID] = @AppointmentID">
    <InsertParameters>
        <asp:Parameter Name="Subject" Type="String" />
        <asp:Parameter Name="Start" Type="DateTime" />
        <asp:Parameter Name="End" Type="DateTime" />
    </InsertParameters>
    <UpdateParameters>
        <asp:Parameter Name="Subject" Type="String" />
        <asp:Parameter Name="Start" Type="DateTime" />
        <asp:Parameter Name="End" Type="DateTime" />
        <asp:Parameter Name="AppointmentID" Type="Int32" />
    </UpdateParameters>
    <DeleteParameters>
        <asp:Parameter Name="AppointmentID" Type="Int32" />
    </DeleteParameters>
</asp:SqlDataSource>
<asp:SqlDataSource ID="GridDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:portal %>"
    SelectCommand="SELECT [AppointmentID], [Start], [End], [Subject], [Due], [Priority] FROM [Appointments] WHERE ([Start] IS NULL) AND ([End] IS NULL)"
    UpdateCommand="UPDATE [Appointments] SET [Start] = @Start, [End] = @End, [Subject] = @Subject, [Due] = @Due, [Priority] = @Priority WHERE AppointmentID = @AppointmentID"
    InsertCommand="INSERT INTO [Appointments] ([Subject], [Due], [Priority]) VALUES (@Subject, @Due, @Priority)">
    <UpdateParameters>
        <asp:Parameter Name="Subject" Type="String" />
        <asp:Parameter Name="Start" Type="DateTime" />
        <asp:Parameter Name="End" Type="DateTime" />
        <asp:Parameter Name="Due" Type="DateTime" />
        <asp:Parameter Name="Priority" Type="String" />
        <asp:Parameter Name="AppointmentID" Type="Int32" />
    </UpdateParameters>
    <InsertParameters>
        <asp:Parameter Name="Subject" Type="String" />
        <asp:Parameter Name="Due" Type="DateTime" />
        <asp:Parameter Name="Priority" Type="String" />
    </InsertParameters>
</asp:SqlDataSource>

[Peter]

Hi Ty,

Since you use a user control, the client ID of the hidden field is modified. You need to get it from the server with the following code:

$get('<%=TargetSlotHiddenField.ClientID %>').value = timeSlot.get_index();

Greetings,
Peter
the Telerik team

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