[Solved] EnableViewState and DataSourcePersistenceMode

[Jay]

Is EnableViewState required to use custom paging and data binding? If I set EnableViewState to false,  RadGrid1_NeedDataSource always sets CurrentPageIndex to 0.

I have seen some help pages that say ViewState is NOT required for paging (and custom sorting).

I have seen other articles (for ASP.NET RadControls) that say set DataSourcePersistenceMode of the grid to NoPersistence to reduce the footprint.

Basically I want to reduce the VIEWSTATE (I do not want any of the data stored in VIEWSTATE -- it is created in the RadGrid1_NeedDataSource when needed.

[Vlad]

Hi Jay,

I have made for you small example to illustrate you how to achieve your goal in your scenario. You can find the example attached.

Greetings,
Vlad
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[Jay]

Thanks for the reply but I think something is wrong ...

In the sample you attached, I placed a breakpoint in RadGrid1_NeedDataSource and noticed it was called twice for each page. Additionally, it did not seem to be implementing custom paging correctly. For page 4, it was returning 40 items intead of 10. For page 9, it was returning 90 items instead of 10, etc.

In the custom paging sample "Grid\Examples\Programming\CustomPaging", it uses custom paging and only calls RadGrid1_NeedDataSource once per page. And it only fills a single page at a time ... not every page up to the current.

How do I remove the viewstate from that sample (I just want to remove the overhead of saving all the data since custom paging is being used)?

Thanks again for great support!!

[Vlad]

Hi Jay,

Indeed you are right. There is a small problem with my project and you can change:

    protected void RadGrid1_ItemCommand(object source, GridCommandEventArgs e)
    {
        if (e.CommandName == RadGrid.PageCommandName ||
            e.CommandName == RadGrid.SortCommandName)
        {
            isSorting = true;
            RadGrid1.DataSource = null;
            RadGrid1.Rebind();
        }
    }
to

    protected void RadGrid1_ItemCommand(object source, GridCommandEventArgs e)
    {
        if (e.CommandName == RadGrid.PageCommandName ||
            e.CommandName == RadGrid.SortCommandName)
        {
            isSorting = (e.CommandName == RadGrid.SortCommandName);
            RadGrid1.DataSource = null;
            RadGrid1.Rebind();
        }
    }

NeedDataSource will be called twice because the grid ViewState is disabled - you can check these help articles for more info:

http://www.telerik.com/help/radcontrols/prometheus/grdRebindGridOnCommandWithDataSourcePersistenceModeNoPersistence.html
http://www.telerik.com/help/radcontrols/prometheus/grdEventSequence.html

Please read DataSourcePersistenceMode = "NoPersistence" as EnableViewState = false on both links.

Generally when traditional paging is used (paged data-source) the grid will retrieve all data source items however all ViewState operations will be only with the current page items/controls (you can check the ViewState in the attached project) and my suggestion is to use turned off ViewState with traditional paging in your case.

You can find attached modified version of the previous example.


Best wishes,
Vlad
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[Jay]

Thanks, but when I made that change, the paging does not seem to work. When I navigate to page 7, it shows page 2, Then when I navigate to page 2, it shows page 7.

Thanks,
Jay

[Ves]

Hi Jay,

Please, find attached an updated version of the first sample provided by Vlad, that does not suffer from this issue. Hope this helps.

Kind regards,
Ves
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center