NestedViewTemplate DataBinding

[Robert]

I have a NestedViewTemplate which will contain several labels and another RadGrid. Because it's expensive to get the data for the labels and nested grid, I'd like to do this only when the NestedViewTemplate is visible.

I set the HierarchyLoadMode to ServerOnDemand and registered for the ItemDataBoundEvent. In the ItemDataBound event, I check the ItemType, and if it's NestedView, I do my expensive data lookups and bind to the labels/grid.

This works great, except that the NestedView items are being databound not when I expand the item in the grid, but instead when the grid is initially databound.

What am I doing wrong?

[Tsvetoslav]

Hello Robert,

Indeed, you are correct in observing this behavior  - RadGrid does not support ServerOnDemand binding with NestedViewTemplate. When the ServerOnDemand mode is specified, then the main grid table reconstructs its items from the ViewState which means that the expanded item won't be databound. If the parent item is not databound, it follows that the nested view template related to it cannot be databound. For this reason, RadGrid always binds all of its nested view items on initial load except for the case demonstrated in the following online example: NestedViewTemplate Relations.

I hope this helps.

Best Regards,
Tsvetoslav
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Check out the tips for optimizing your support resource searches.

[Robert]

If I wanted on-demand loading, how would I achieve this?

[Sebastian]

Hello Robert,

Review the approach with NestedView template relations presented in the demo and modify your logic accordingly to take advantage of it and have load-on-demand mode for the expanded records. Otherwise consider the technique with dynamic panel visibility changing presented on this online demo of the product.

Greetings,
Sebastian
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Check out the tips for optimizing your support resource searches.

[Jack Voss]

Hello,

I'm using the method  "dynamic panel visibility changing presented on this online demo" as presented above.  The datasources are bound in the code behind page using the OnNeedDataSource event.  The problem I have is that OnNeedDataSource for the nested sub grids are not being fired until the Master grid is expanded once and then collapsed.

So if the user expands the grid, then collapses it, then expands it again, we can see the grid with the data.  Nothing happens on the first expansion of the grid.

At this point I'm not really sure what to do, so any adivce would be appreciated. 

Thank you

[Tsvetina]

Hello Jack,

When you use NeedDataSource to populate the nested grid, you might need to call rebind for it after it has been made visible. In other words, try calling Rebind() for the nested grid after you have set the panel's Visible property to true.

This happens because when the grid is not initially visible, it does not bind automatically:
http://www.telerik.com/help/aspnet-ajax/grid-visible-invisible-conventions.html

Greetings,
Tsvetina
the Telerik team

[Jack Voss]

Thank you,  I thought that might be the case.

I wound up implementing this :

protected void grdCMT_ItemCommand(object source, GridCommandEventArgs e)
        {
            if (e.CommandName == RadGrid.ExpandCollapseCommandName && e.Item is GridDataItem && !e.Item.Expanded)
            {
                RadAjaxPanel rpInnerPanel1;
                rpInnerPanel1 = (RadAjaxPanel)((GridDataItem)e.Item).ChildItem.FindControl("InnerPanel1");
                //RadAjaxPanel rpInnerPanel1 = (RadAjaxPanel)(e.Item.FindControl("InnerPanel1"));
                rpInnerPanel1.Visible = true;
                RadMultiPage rmMultiPage1 = (RadMultiPage)(rpInnerPanel1.FindControl("RadMultiPage1"));
                RadPageView rpvInstalls = (RadPageView)(rmMultiPage1.FindControl("rpvInstalls"));
                RadGrid rgInstalls = (RadGrid)(rpvInstalls.FindControl("rgrdInstalls"));
                rgInstalls.Rebind();
            }
            else if (e.CommandName == RadGrid.ExpandCollapseCommandName && e.Item is GridDataItem && e.Item.Expanded)
            {
                RadAjaxPanel rpInnerPanel1;
                rpInnerPanel1 = (RadAjaxPanel)((GridDataItem)e.Item).ChildItem.FindControl("InnerPanel1");
                rpInnerPanel1.Visible = false;
            }
        }

It seems to work fine now,  I'm not sure if I needed to search through the child controls like that, but it works right now.

Thank you

[Sridharan]

I tried to control the on demand loading of radgrid inside nestedviewtemplate based on the code snippets in the demo. But the data binding still happens for radgrids inside the nestedviewtemplate along with master grid data.

Here is my snippets of aspx
......
<telerik:RadAjaxPanel ID="RadAjaxPanel1" runat="server" >
<telerik:RadGrid ID="MasterGrid" datasourceid="master_table_ds" runat="server"
AllowFilteringByColumn="True" AllowSorting="True" ClientSettings-ReorderColumnsOnClient="True"
AllowPaging="True" PageSize="2" MasterTableView-AllowCustomSorting="True" AllowAutomaticUpdates="True"
OnColumnCreated="RadGrid_ColumnCreated" OnItemDataBound="MasterGrid_ItemDataBound">

<GroupingSettings CaseSensitive="false" />

<MasterTableView DataKeyNames="ProjectID" EnableHeaderContextMenu="true"
AutoGenerateColumns="false" HierarchyLoadMode="ServerOnDemand" ShowHeadersWhenNoRecords="false">

...
...
<Columns>
...
..
</Columns>
..
<NestedViewTemplate>
<asp:Panel ID="ProjectDetailsContainer" CssClass="viewWrap" Visible="false" runat="server">

<div class="bgg-white-darkslategray" style="padding-left:10px; padding-top:8px; width:100%; overflow:auto;">
..
..
<telerik:RadTabStrip runat="server" ID="Tabstrip" MultiPageID="tabPages" SelectedIndex="0">
<Tabs>
<telerik:RadTab Text="Project Info" PageViewID="PageView1" runat="server" >
</telerik:RadTab>

<telerik:RadTab Text="Roles" PageViewID="PageView2" runat="server">
</telerik:RadTab>


 </Tabs>
</telerik:RadTabStrip>


<telerik:RadMultiPage runat="server" ID="tabPages" SelectedIndex="0" RenderSelectedPageOnly="false">
 
 
<telerik:RadPageView ID="PageView1" runat="server" >
<asp:Label ID="projectIDLabel1" Font-Bold="true" Font-Italic="true" Text='<%# Eval("ProjectID") %>'
Visible="false" runat="server">
</asp:Label>
<telerik:RadGrid ID="ProjRecordDetailGrid" DataSourceID="detail_table1_ds" runat="server"  >
..
..


<asp:ObjectDataSource ID="detail_table1_ds" SelectMethod="GetGridData" EnableCaching="true"
OnSelecting="detail_table_ds_Selecting"  TypeName="dataSourceObject" CacheDuration="10" runat="server" >
<SelectParameters>
<asp:ControlParameter ControlID="projectIDLabel1" Name="ProjectID" Type="String" Direction="Input" />
  <asp:Parameter Name="datasource" DefaultValue="ProjectsForm" />
</SelectParameters>
</asp:ObjectDataSource>
 ..
</telerik:RadPageView>
</telerik:RadMultiPage>

</div>
</asp:Panel>
</NestedViewTemplate>

 </MasterTableView>
 
</telerik:RadGrid>
</telerik:RadAjaxPanel>
</div>

-------------------------------------

Code behind logic is similar to the one in demo

Protected Sub MasterGrid_PreRender(ByVal sender As Object, ByVal e As EventArgs) Handles MasterGrid.PreRender

If Not Page.IsPostBack Then

MasterGrid.MasterTableView.Items(0).Expanded = True

MasterGrid.MasterTableView.Items(0).ChildItem.FindControl("ProjectDetailsContainer").Visible = True

End If

End Sub



Protected Sub MasterGrid_ItemCommand(ByVal source As Object, ByVal e As GridCommandEventArgs) Handles MasterGrid.ItemCommand

If e.CommandName = RadGrid.ExpandCollapseCommandName And TypeOf e.Item Is GridDataItem Then

DirectCast(e.Item, GridDataItem).ChildItem.FindControl("ProjectDetailsContainer").Visible = Not e.Item.Expanded

End If

End Sub



Protected Sub MasterGrid_ItemCreated(ByVal sender As Object, ByVal e As GridItemEventArgs) Handles MasterGrid.ItemCreated

If TypeOf e.Item Is GridNestedViewItem Then
 
e.Item.FindControl("ProjectDetailsContainer").Visible = (DirectCast(e.Item, GridNestedViewItem)).ParentItem.Expanded


End If

End Sub

===================================

Please advise if I am missing anything or doing anything incorrectly.

thanks in advance,
Sri

 

 

[Eyup]

Hello Sridharan,

I'm sending a sample RadGrid web site to demonstrate optimal configuration of nested grid bindings. Please run the attached application and let me know if it helps you.

Regards,
Eyup
Telerik