"Failed to load viewstate" error when updating/canceling an inplace edit

[Dmitri]

I have a TreeList object that allows inplace editing. Two of the columns are TemplateColumns that display using a label but edit using a RadComboBox. When I press the edit button everything works fine (my drop downs load and everything) but when i press Cancel or Update after editing the system throws a "Failed to load viewstate" error. Treelist code below:

                <telerik:RadTreeList ID="rtl_Content" runat="server" 
                    AutoGenerateColumns="False" DataKeyNames="ID" ParentDataKeyNames="ID_Parent" Skin="Office2010Blue" EditMode="InPlace">
                    <ExportSettings ExportMode="RemoveControls"><Pdf PageHeight="11in" PageWidth="8.5in"></Pdf></ExportSettings>
                    <Columns>
                        <telerik:TreeListBoundColumn DataField="ID" UniqueName="column" Visible="False">
                        </telerik:TreeListBoundColumn>
                        <telerik:TreeListBoundColumn DataField="ID_Parent" UniqueName="column1" Visible="False">
                        </telerik:TreeListBoundColumn>
                        <telerik:TreeListTemplateColumn DataField="Display" HeaderText="Content" UniqueName="col_Display">
                            <ItemTemplate>
                                <asp:Label ID="lblCDisplay" runat="server" Text='<%# Eval("Display") %>' />
                            </ItemTemplate>
                            <EditItemTemplate>
                                <telerik:RadTextBox runat="server" ID="rtb_CDisplay" Skin="Office2010Blue" Text='<%# Bind("Display") %>' Width="100%" Height="40px" TextMode="MultiLine" />
                            </EditItemTemplate>
                        </telerik:TreeListTemplateColumn>
                        <telerik:TreeListTemplateColumn DataField="Type" HeaderText="" UniqueName="col_Type">
                            <ItemTemplate>
                                <asp:Label ID="lblCType" runat="server" Text='<%# Eval("Type") %>' />
                            </ItemTemplate>
                            <EditItemTemplate>
                                <telerik:RadComboBox runat="server" ID="rcb_CType" Skin="Office2010Blue" SelectedValue='<%# Bind("Type") %>' DataSource='<%# (new string[] {"Team Lead", "EDA"}) %>' Width="100%" />
                            </EditItemTemplate>
                            <ItemStyle Width="75px" HorizontalAlign="Center" />
                            <HeaderStyle Width="75px" HorizontalAlign="Center" />
                        </telerik:TreeListTemplateColumn>
                        <telerik:TreeListEditCommandColumn UniqueName="EditColumn" ButtonType="LinkButton" ShowAddButton="true" HeaderText="">
                            <ItemStyle HorizontalAlign="Center" Width="100px" />
                            <HeaderStyle HorizontalAlign="Center" Width="100px" />
                        </telerik:TreeListEditCommandColumn>
                        <telerik:TreeListButtonColumn UniqueName="DeleteColumn" ButtonType="LinkButton" HeaderText="" CommandName="Delete" Text="Delete">
                            <ItemStyle HorizontalAlign="Center" Width="50px" />
                            <HeaderStyle Width="50px" />
                        </telerik:TreeListButtonColumn>
                    </Columns>
                </telerik:RadTreeList>

Not sure if it makes a difference but the whole thing is inside a RadPageView

[Antonio Stoilkov]

Hi Dmitri,

I tried to replicate the issue which you described, but to no avail. Attached to this message, you will find the code which I used for testing. Please, take a look at it and let me know if there are any differences at your end, which I may be leaving out.

Note that failed Viewstate load could be caused by dynamically adding controls in Page_Load method. It is more likely that server-side code causes the issue and not the declaration of the controls.

Greetings,
Antonio Stoilkov
the Telerik team