Last Updated: 27 May 2020 10:45 by ADMIN
A NullReferenceException is raised when trying to edit a GridViewMultiColumnComboBoxColumn and the RadGridView's ItemsSource is a DataView.
Last Updated: 27 May 2020 06:57 by ADMIN
Created by: LindenauAtSOG
Comments: 3
Category: GridView
Type: Bug Report
As a Followup to this (Bad performance with grouping)Forumpost I managed to reproduce the issue now.
Since i cannot upload zip-files in the Forum I am doing it here.

The problem is, that a single grouping dramatically increases the time for sorting the values.
When the grouping is not present, sorting the same column is much faster.

It appears that it is related to the ammount of columns in total (not grouped).
The ammount of records is not so important, 100 (as in the attached sample) should not be significant.
Last Updated: 18 May 2020 10:23 by ADMIN

When you have rows grouped by null value and you try to move one of the rows to another group, a NullReferenceException is thrown.

This is reproducible only when DataView is used as ItemsSource of RadGridView.

To work this around, avoid using null values. Or avoid using DataView.

Last Updated: 05 May 2020 08:02 by ADMIN
If in the content of RadGridView.ControlPanelItem has a binding with a RelativeSource or ElementName and the grid is placed in the collapsed UserControl, a binding error is thrown in the output window.
Last Updated: 20 Mar 2020 14:58 by ADMIN
Last Updated: 20 Mar 2020 14:49 by ADMIN
When using Entity Framework Core 3 an InvalidOperationException is received upon adding an AggregateFunction to a column. 
Last Updated: 18 Mar 2020 08:22 by ADMIN

To reproduce this:

  1. Set the GroupRenderMode of RadGridView to Flat.
  2. Page RadGridView using RadDataPager.
  3. Scroll to the last row in the view. Or scroll to any row so that few of the rows above are not longer visible.
  4. Expand the row details and scroll down more until only the parent row is visible.
  5. Collapse the row details. At this point, the vertical scrollbar disappears and the upper rows are not brought into the view as expected when the row details gets collapsed.

To work this around call the Rebind() method of RadGridView on RowDetailsVisibilityChanged event.


private void RadGridView_RowDetailsVisibilityChanged(object sender, Telerik.Windows.Controls.GridView.GridViewRowDetailsEventArgs e)
	if (e.Visibility == Visibility.Collapsed)


Last Updated: 05 Feb 2020 13:51 by ADMIN
DataContext of rows is sometimes null when UI virtualization is enabled in the Flat group render mode.
Last Updated: 17 Jan 2020 15:27 by ADMIN

We noticed that RadGridView does not get garbagecollected sometimes.
So i fired up  a memory analyzer to see what is going on.

This is the graph that shows that the RadGridView is causing a leak. The only references that keep the GridView from getting collected are those two WeakEventListeners

To further investigate i decompiled GridViewDataControl and could identify the culprit.

private void SubscribeToDispatcherShutdown()
      if (this.dispatcherShutdownListener != null)
      this.dispatcherShutdownListener = new WeakEventListener<GridViewDataControl, object, EventArgs>(this);
      this.dispatcherShutdownListener.OnEventAction = (Action<GridViewDataControl, object, EventArgs>) ((grid, source, eventArgs) => grid.OnDispatcherShutdownFinished(source, eventArgs));
      this.dispatcherShutdownListener.OnDetachAction = (Action<WeakEventListener<GridViewDataControl, object, EventArgs>>) (weakEventListener => this.Dispatcher.ShutdownFinished -= new EventHandler(this.dispatcherShutdownListener.OnEvent));
      this.Dispatcher.ShutdownFinished += new EventHandler(this.dispatcherShutdownListener.OnEvent);

In the second line from the botton

... weakEventListener => this.Dispatcher.ShutdownFinished -
... you are using 'this.Dispatcher...' which causes the leak since the Action will implicitly capture the 'this' reference.
Which kind of defeats the prupose of having a WeakReference inside your WeakEventListener.

Sadly i cannot figure out how it happens, but i think its only when Detach (FrameworkElement.Unloaded ultimately) is not called.
While this is the actual issue, i thought I'd share this with you so you.

Last Updated: 17 Dec 2019 10:06 by ADMIN
When a frozen column is resized to fill the entire RadGridView, there isn't an option to reduce its size in order to bring the other columns into view.
Last Updated: 25 Nov 2019 14:00 by ADMIN
Scrollviewer is not updated when row details are collapsed.
Last Updated: 17 Sep 2019 09:28 by ADMIN

If you have the following model, the columns that show the Test and Date properties (in the derived class) cannot be sorted or filtered.


public class RowModel
    public int Id { get; set; }
    public Bar FredBar { get; set; }
public class Fred : Bar
    public DateTime Date { get; set; }
    public string Test { get; set; }
public abstract class Bar
    public string Title { get; set; }
    public double Value { get; set; }       

    <telerik:GridViewDataColumn DataMemberBinding="{Binding Id}" />               
    <telerik:GridViewDataColumn DataMemberBinding="{Binding FredBar.Title}" />
    <telerik:GridViewDataColumn DataMemberBinding="{Binding FredBar.Value}" />
    <telerik:GridViewDataColumn DataMemberBinding="{Binding FredBar.Date}" />
    <telerik:GridViewDataColumn DataMemberBinding="{Binding FredBar.Test}" />

To work this around, set the IsCustomSorting property of the corresponding columns and implement a custom sorting in the Sorting event of RadGridView.

Last Updated: 16 Sep 2019 12:21 by ADMIN

Bind a grid to a DataView

Start editing and change the values of a few cells.

Press Escape twice to cancel the edit of the entire row.

Expected: the values return to the old values

Actual: the values remain the last entered ones

Last Updated: 21 Aug 2019 13:07 by ADMIN
When invalid rows that were loaded but not in viewport get valid, the invalid state (row validation indicator) is still visible.
Last Updated: 11 Mar 2019 14:39 by ADMIN
Created by: Ivan Ivanov
Comments: 0
Category: GridView
Type: Bug Report
Unhandled exception System.InvalidOperationException: The calling thread cannot access this object because a different thread owns it.
   at System.Windows.Threading.Dispatcher.VerifyAccess()
   at System.Windows.DependencyObject.GetValue(DependencyProperty dp)
   at Telerik.Windows.Data.SortDescriptorBase.get_SortDirection()
   at Telerik.Windows.Data.Expressions.SortDescriptorCollectionExpressionBuilder.Sort()
   at Telerik.Windows.Data.QueryableExtensions.Sort(IQueryable source, IEnumerable`1 sortDescriptors)
   at Telerik.Windows.Data.QueryableExtensions.Sort(IQueryable source, SortDescriptorCollection sortDescriptors)
. . .
Last Updated: 06 Mar 2019 13:54 by ADMIN
When there are 1000 (reproduce with 500) distinct values in the Popup filter and we try to select all of them it took 15 seconds and more when using ICustomPropertyProvider.
Last Updated: 08 Feb 2019 08:54 by ADMIN
This happens in the following scenarios:

1. The FilterMemberPath points to the Date property of a DateTime one.
2. The column name contains "[]" square brackets.
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