Hi there

During testing, I noticed that I can sometimes provoke a NullReferenceException in the grid. The stacktrace is below. The strange thing is: The last invoked line in my application does not even access the grid, it merely passes a refrence to a static helper method (which is never invoked):

GroupEditor.xaml Line 100: UIHelper.SelectFirstVisibleRecord(groupGrid);

The next method on the trace is an internal method of the grid. The only hint I can give you is that I'm evaluating active records in two events that follow each other nearly immediately, but on a single thread. If the grid spans any background threads during binding, this may be a reason. It's also noteworthy that I have a *really* hard time to reproduce the issue (need to wildly provoke refreshes of the data source for minutes).

Just for the record, here's what non-invoked method contains (nothing too fancy here...)

    public static bool SelectFirstVisibleRecord(XamDataGrid grid)
    {
      ViewableRecordCollection records = grid.ViewableRecords;
      if (records.Count > 0)
      {
        grid.SelectedItems.Records.Clear();

        //might be redundant but resolved issues with 7.2 beta
        grid.ActiveRecord = null;
        grid.ActiveRecord = records[0];
        records[0].IsSelected = true;
        return true;
      }
      else
      {
        return false;
      }
    }

Cheers,

Philipp 

An unhandled exception occurred:

System.NullReferenceException: Object reference not set to an instance of an object.

   at Infragistics.Windows.DataPresenter.DataPresenterBase.a(Record A_0, Boolean A_1)

   at Infragistics.Windows.DataPresenter.DataPresenterBase.c(Record A_0, Boolean A_1)

   at Infragistics.Windows.DataPresenter.DataPresenterBase.c(DependencyObject A_0, Object A_1)

   at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, OperationType operationType)

   at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, OperationType operationType, Boolean isInternal)

   at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)

   at Infragistics.Windows.DataPresenter.DataPresenterBase.set_ActiveRecord(Record value)

   at CT.ManagementStudio.UI.DataModel.GroupEditor.BindGroups() in P:\My Data\Evolve\Projects\ABB\CT\src\trunk\Tools\CT Management Studio\Management Studio\UI\DataModel\GroupEditor.xaml.cs:line 100

   at CT.ManagementStudio.UI.DataModel.GroupEditor.OnProjectPropertyChanged(String propertyName) in P:\My Data\Evolve\Projects\ABB\CT\src\trunk\Tools\CT Management Studio\Management Studio\UI\DataModel\GroupEditor.xaml.cs:line 48

   at CT.ManagementStudio.UI.Common.CtmsUserControl.OnProjectPropertyChangedInternal(Object sender, PropertyChangedEventArgs e) in P:\My Data\Evolve\Projects\ABB\CT\src\trunk\Tools\CT Management Studio\Management Studio\UI\Common\CtmsUserControl.cs:line 150

   at System.ComponentModel.PropertyChangedEventHandler.Invoke(Object sender, PropertyChangedEventArgs e)

   at CT.ManagementStudio.ViewModel.CtmsProject.RaisePropertyChangedEvent(String propertyName) in P:\My Data\Evolve\Projects\ABB\CT\src\trunk\Tools\CT Management Studio\Management Studio\ViewModel\CtmsProject.cs:line 392

   at CT.ManagementStudio.ViewModel.CtmsProject.set_ActiveGroup(SyncGroup value) in P:\My Data\Evolve\Projects\ABB\CT\src\trunk\Tools\CT Management Studio\Management Studio\ViewModel\CtmsProject.cs:line 172

   at CT.ManagementStudio.UI.DataModel.DataEditorUtil.AddGroup(CtmsProject Project, SyncGroup parentGroup) in P:\My Data\Evolve\Projects\ABB\CT\src\trunk\Tools\CT Management Studio\Management Studio\UI\DataModel\DataEditorUtil.cs:line 76

   at CT.ManagementStudio.UI.DataModel.GroupTree.AddItem(Object sender, ExecutedRoutedEventArgs e) in P:\My Data\Evolve\Projects\ABB\CT\src\trunk\Tools\CT Management Studio\Management Studio\UI\DataModel\GroupTree.xaml.cs:line 100

   at System.Windows.Input.CommandBinding.OnExecuted(Object sender, ExecutedRoutedEventArgs e)

   at System.Windows.Input.CommandManager.ExecuteCommandBinding(Object sender, ExecutedRoutedEventArgs e, CommandBinding commandBinding)

   at System.Windows.Input.CommandManager.FindCommandBinding(CommandBindingCollection commandBindings, Object sender, RoutedEventArgs e, ICommand command, Boolean execute)

   at System.Windows.Input.CommandManager.FindCommandBinding(Object sender, RoutedEventArgs e, ICommand command, Boolean execute)

   at System.Windows.Input.CommandManager.OnExecuted(Object sender, ExecutedRoutedEventArgs e)

   at System.Windows.UIElement.OnExecutedThunk(Object sender, ExecutedRoutedEventArgs e)

   at System.Windows.Input.ExecutedRoutedEventArgs.InvokeEventHandler(Delegate genericHandler, Object target)

   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)

   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)

   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)

   at System.Windows.UIElement.RaiseEventImpl(RoutedEventArgs args)

   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)

   at System.Windows.Input.RoutedCommand.ExecuteImpl(Object parameter, IInputElement target, Boolean userInitiated)

   at System.Windows.Input.RoutedCommand.ExecuteCore(Object parameter, IInputElement target, Boolean userInitiated)

   at System.Windows.Input.CommandManager.TransferEvent(IInputElement newSource, ExecutedRoutedEventArgs e)

   at System.Windows.Input.CommandManager.OnExecuted(Object sender, ExecutedRoutedEventArgs e)

   at System.Windows.UIElement.OnExecutedThunk(Object sender, ExecutedRoutedEventArgs e)

   at System.Windows.Input.ExecutedRoutedEventArgs.InvokeEventHandler(Delegate genericHandler, Object target)

   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)

   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)

   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)

   at System.Windows.UIElement.RaiseEventImpl(RoutedEventArgs args)

   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)

   at System.Windows.Input.RoutedCommand.ExecuteImpl(Object parameter, IInputElement target, Boolean userInitiated)

   at System.Windows.Input.RoutedCommand.ExecuteCore(Object parameter, IInputElement target, Boolean userInitiated)

   at MS.Internal.Commands.CommandHelpers.CriticalExecuteCommandSource(ICommandSource commandSource, Boolean userInitiated)

   at System.Windows.Controls.MenuItem.InvokeClickAfterRender(Object arg)

   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)

   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
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OK  
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