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Request a Feature Report a Bug
Unplanned
Last Updated: 25 Aug 2025 11:20 by ADMIN
enric
Created on: 07 Dec 2020 14:28
Category: GridView
Type: Bug Report
1
RadGridView: NullReferenceException when call BestFitColumns method and rebind the grid with custom theme

Steps to reproduce:

1. Bind the grid to BindingList

2. Call BestFitColumns method in form's constructor

3. Use Fluent/Crystal theme

4. Rebind the grid by setting DataSource=null

5. Exception is thrown

Stack trace:

en Telerik.WinControls.UI.BestFitHelper.SetColumnWidth(GridViewColumn column, Single desiredWidth)
   en Telerik.WinControls.UI.BestFitHelper.BestFitColumnCore(GridViewColumn column, BestFitColumnMode mode)
   en Telerik.WinControls.UI.BestFitHelper.ProcessRequests()
   en Telerik.WinControls.UI.GridTableElement.UpdateAll()
   en Telerik.WinControls.UI.GridTableElement.UpdateViewCore(Object sender, DataViewChangedEventArgs args)
   en Telerik.WinControls.UI.GridTableElement.UpdateView(Object sender, DataViewChangedEventArgs args)
   en Telerik.WinControls.UI.GridTableElement.ProcessTemplateEvent(GridViewEvent eventData)
   en Telerik.WinControls.UI.GridTableElement.Telerik.WinControls.UI.IGridViewEventListener.ProcessEvent(GridViewEvent eventData)
   en Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessCollection(GridViewEvent gridEvent, PriorityWeakReferenceList list, GridEventProcessMode processMode)
   en Telerik.WinControls.UI.GridViewEventProcessEntity.ProcessEvent(GridViewEvent gridEvent)
   en Telerik.WinControls.UI.GridViewSynchronizationService.NotifyListeners(GridViewEvent gridEvent)
   en Telerik.WinControls.UI.GridViewSynchronizationService.FlushEvents()
   en Telerik.WinControls.UI.GridViewSynchronizationService.DispatchEvent(GridViewEvent gridEvent)
   en Telerik.WinControls.UI.GridViewSynchronizationService.DispatchEvent(GridViewTemplate template, GridViewEvent eventData, Boolean postUI)
   en Telerik.WinControls.UI.GridViewTemplate.DispatchEvent(GridViewEvent gridEvent, Boolean postUI)
   en Telerik.WinControls.UI.GridViewTemplate.DispatchDataViewChangedEvent(Object sender, DataViewChangedEventArgs args)
   en Telerik.WinControls.UI.GridViewTemplate.OnViewChanged(Object sender, DataViewChangedEventArgs e)
   en Telerik.WinControls.UI.MasterGridViewTemplate.OnViewChanged(Object sender, DataViewChangedEventArgs e)
   en Telerik.WinControls.UI.GridViewTemplate.CollectionView_CollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.RadCollectionView`1.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
   en Telerik.WinControls.Data.RadDataView`1.RebuildData(Boolean notify)
   en Telerik.WinControls.Data.RadDataView`1.RefreshOverride()
   en Telerik.WinControls.Data.RadDataView`1.ProcessCollectionChanged(NotifyCollectionChangedEventArgs args)
   en Telerik.WinControls.Data.RadCollectionView`1.source_CollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.RadListSource`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   en Telerik.WinControls.Data.RadListSource`1.EndUpdate(Boolean notifyUpdates)
   en Telerik.WinControls.Data.RadListSource`1.Initialize()
   en Telerik.WinControls.Data.RadListSource`1.Bind(Object dataSource, String dataMember)
   en Telerik.WinControls.Data.RadListSource`1.set_DataSource(Object value)
   en Telerik.WinControls.UI.GridViewTemplate.set_DataSource(Object value)
   en Telerik.WinControls.UI.RadGridView.set_DataSource(Object value)

2 comments
ADMIN
Dinko | Tech Support Engineer
Posted on: 25 Aug 2025 11:20

Hello Martin,

Thank you for the additional details. This scenario will be taken into account when fixing this behavior. 

Regards,
Dinko | Tech Support Engineer
Progress Telerik

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Martin
Posted on: 23 Aug 2025 10:21

I've had the same problem, but not related to themes (I suspect).

In my case, I was building a form with a RadGridView while layout was suspended. I suspect that columns are added to the BestFitQueue inside the BestFitHelper, because they need to be calculated later.

By some business rule on our side, the form was built twice (the second time a bit different). So the previous columns were removed from the RadGridView but I suspect not removed from the BestFitQueue.

When layout was resumed, the column sizes needed to be calculated, and it iterates through the queue, including the columns that are no longer part of the RadGrdiView, resulting in an NullReferenceException.

This is de code that breaks, inside SetColumnWith:

if (column.OwnerTemplate.AutoSizeColumnsMode == GridViewAutoSizeColumnsMode.Fill && tableViewRowLayout != null)

OwnerTemplate (the owning RadGridView) has been set to NULL, so this causes the exception.

It can be fixed in two ways:

A: Lazy inside SetColumnWith, change the first line:

if (column != null)

into:

if (column != null && column.OwnerTemplate != null)

or B: When a column is removed from RadGridView, also remove it from the BestFitQueue.

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