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Bring the selected Item into View

13 Answers 783 Views

GridView

This is a migrated thread and some comments may be shown as answers.

Nils asked on 18 Jan 2010, 10:48 AM

Hi.
I Have a RadGridView with a vertical scrollbar.
Is there a possibility to bring a certain Item into view.
I have tried Selected and Current however, the scrollbar remains unchanged.
Ideally I need something like:

    
            var newItemInMyList = GetNewItem();  
        
            this.ItemsSource.Add(newItemInMyList);  
        
            this.SelectedItem = newItemInMyList;  
        
            this.CurrentItem = newItemInMyList;  
        
            this.radGridView1.BringIntoView(newItemInMyList);

However if that is not possibile I would settle with bringing the scrollbar to the bottom of the Grid. (For the new Item woll most likely be added at the end of the list...)

Yours,
Nils

13 Answers, 1 is accepted

Accepted

answered on 08 Jan 2015, 08:04 PM

My small project doesn't reproduce the problem.

My suspect is the SelectedItem="{Binding SelectedProperty}" line of xaml:

<telerik:RadGridView x:Name="gvProperties" Grid.Row="1"
ItemsSource="{Binding DataContext.Properties, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=telerik:RadRibbonWindow}}"
SelectedItem="{Binding SelectedProperty}" <<<<<<<<<<<<<< this line right here <<<<<<<<<<<<<<

I highly suspect that the RadGridView.SelectedItem is being overwritten by the telerik library due to this binding. All my other RadGridViews do not have this problem and do not use SelectedItem binding. Is this a known issue? how do I reset the selected item after sorting? RadGridView.SelectedItem is overwritten AFTER the SortED routine exits.

answered on 13 Jan 2015, 03:45 PM

I haven't posted here in 5 days. My resolution was posted to the support ticket, but your users might like to know the resolution we came to. We were querying the data database as IQueriable. As an Iqueriable the Selected item was being changed to null and then to the new index of the reordered items. (This caused the OnPropertyChanged method to be fired twice.) By casting the results of the query to IEnumerable using .ToList() (or alternately "As Enumerable") the "SelectedItem" in the Rad Grid view stays intact.

This is directly related to the problem of scrolling into view. The control would scroll to the "index" of the reordered/requeried list of items, but the previously selected item was moved off the screen. Now... We are not done. The ScrollintoView and ScrollIntoViewAsync still did not work (I would say that is a bug.) - (And BringIndexIntoView only brings something into the view at the top or bottom). We wanted the selected item to always appear at the top of the current view. We required a custom method to find the index of the selected item and use BringIndexIntoView. I will post that code below:

public static void FindItemInTheList(this RadGridView grid, object item)
{
grid.BringIndexIntoView(grid.Items.IndexOf(item));

GridViewRow targetRow = grid.ChildrenOfType<GridViewRow>().Where(r => r.Item == item).FirstOrDefault();
var scrollViewer = Util.GetScrollViewer(grid) as ScrollViewer;

//scroll the selected item up until it is not visible
double lastVerticaleOffset = -1;
while (targetRow != null && targetRow.IsVisible && scrollViewer.CanContentScroll && scrollViewer.VerticalOffset != lastVerticaleOffset)
{
lastVerticaleOffset = scrollViewer.VerticalOffset;
scrollViewer.LineDown();
grid.UpdateLayout();
}

//scroll the row back into view
grid.BringIndexIntoView(grid.Items.IndexOf(item));
}

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Bring the selected Item into View

13 Answers, 1 is accepted