Self recycle RowDetails

[Arthur]

Hi,

I am just trying to improve scroll performance, when the RowDetailsVisibilityMode is set to "Visible", because it is slow for complex detail controls.
Now I am doing this:

<DataTemplate x:Key="DetailTemplate">
    <ContentControl/>
</DataTemplate>

In code behind:

List<TextBlock> notInUse = new List<TextBlock>();

public DataListEditor()
{
    InitializeComponent();

    for (int i = 0; i < 100; ++i)
    {
        TextBlock tb = new TextBlock();
        notInUse.Add(tb);
    }

    dataListGrid.LoadingRowDetails += dataListGrid_LoadingRowDetails;
    dataListGrid.UnloadingRowDetails += dataListGrid_UnloadingRowDetails;
}

void dataListGrid_UnloadingRowDetails(object sender, Telerik.Windows.Controls.GridView.GridViewRowDetailsEventArgs e)
{
    ContentControl c = e.DetailsElement as ContentControl;

    TextBlock tb = c.Content as TextBlock;

    if (tb != null)
    {
        c.Content = null;
        notInUse.Add(tb);
    }
}

void dataListGrid_LoadingRowDetails(object sender, Telerik.Windows.Controls.GridView.GridViewRowDetailsEventArgs e)
{
    ContentControl c = e.DetailsElement as ContentControl;

    if (c.Content == null)
    {
        Binding b = new Binding("Roles[0].DisplayName");
        b.Source = e.Row.DataContext;

        TextBlock tb = notInUse[0];
        notInUse.RemoveAt(0);

        tb.SetBinding(TextBlock.TextProperty, b);
        c.Content = tb;
    }
}

In other words: I try to recycle detail controls, so that there is no need to recreate them. This works fine, when I am only scrolling. But if I resize the window, the DetailsPresenter of a row seems not to be measured to its content, so the text block is there with the right height, but its visual ancestors have a wrong height and the textblock is not visible. Is there a workaround to solve this?

Thanks

[Arthur]

OK,

the problem can be reformulated: Forget the code behind. If the details DataTemplate contains a ContentControl for example with MinHeight = 20 the problem  still occurs, because not all row details are visible when the window is resized. Is this a bug?

[Arthur]

I have opened a ticket. For those who stumble across the same problem. It seems that if GroupRenderMode is set to "Flat", details are not measured correctly when the GridView is resized. If I set the PART_DetailsPresenter Height via Snoop to the expected size, I can see what I expect.

[Yoan]

Hi Arthur,

Actually, this issue is a known one. It is logged into our Feedback portal as a bug report. You can track its status: Visible RowDetails collapse when GroupRenderMode=Flat and maximize/minimize the window

Regards,
Yoan
Telerik