Hello,

I got an issue with the XamMultiColumnComboEditor control since the the 14.2 service release 2178. This also apply to 15.1 service release 2008.

An invisible UserControl which host a XamMultiColumnComboEditor control raises a "System.NullReferenceException" and crash the application (both VS13 designer & BIN application):

   à Infragistics.Controls.Editors.ComboEditorBase`2.XamWebComboEditor_Loaded(Object sender, RoutedEventArgs e)
   à System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   à System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   à System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   à System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
   à System.Windows.BroadcastEventHelper.BroadcastEvent(DependencyObject root, RoutedEvent routedEvent)
   à System.Windows.BroadcastEventHelper.BroadcastLoadedEvent(Object root)
   à MS.Internal.LoadedOrUnloadedOperation.DoWork()
   à System.Windows.Media.MediaContext.FireLoadedPendingCallbacks()
   à System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   à System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   à System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   à System.Windows.Media.MediaContext.Resize(ICompositionTarget resizedCompositionTarget)
   à System.Windows.Interop.HwndTarget.OnResize()
   à System.Windows.Interop.HwndTarget.HandleMessage(WindowMessage msg, IntPtr wparam, IntPtr lparam)
   à System.Windows.Interop.HwndSource.HwndTargetFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   à MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   à MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   à System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   à MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
   à System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   à MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)

Steps to reproduce

1. Define a simple WPF user control "UserControl1" and add the XamMultiColumnComboEditor:

<UserControl
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:ig="http://schemas.infragistics.com/xaml" xmlns:Custom="http://infragistics.com/Windows" x:Class="WpfApplication1.UserControl1" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <ig:XamMultiColumnComboEditor/>
    Grid> UserControl> 

2. In a window, or page, put that custom control "UserControl1" Inside the second tab - a tab which is not displayed by default

Note: standard WPF TabControl or Infragistics XamTabControl have the same behavior.

<Window xmlns:igWPF="http://schemas.infragistics.com/xaml/wpf" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:ig="http://schemas.infragistics.com/xaml" xmlns:local="clr-namespace:WpfApplication1" x:Class="WpfApplication1.MainWindow"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <igWPF:XamTabControl>
            <igWPF:TabItemEx x:Name="tabItemEx1" Header="tabItemEx1">
                <Grid/>
            igWPF:TabItemEx>             <igWPF:TabItemEx x:Name="tabItemEx2" Header="tabItemEx2">                 <local:UserControl1 />             igWPF:TabItemEx>         igWPF:XamTabControl>     Grid> Window> 

- Close both documents and open again the window : VS13 designer crashes.

- Close both documents, compile and run : application crashes.

Notes:

- If we move the TabControl to the UserControl : KO, same behavior

- If we move UserControl1 to the first tab (the one which is displayed by default) : OK

Lib. reference: InfragisticsWPF4.Controls.Editors.XamComboEditor - 14.2.20142.2178 (was OK in 14.2.20142.2081)

code snippets

MainWindow:

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:ig="http://schemas.infragistics.com/xaml" xmlns:local="clr-namespace:WpfApplication1" x:Class="WpfApplication1.MainWindow"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <local:UserControl1 HorizontalAlignment="Left" Margin="139,142,0,0" VerticalAlignment="Top"/>
    Grid> Window> 

UserControl1 snippet :

<UserControl
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:ig="http://schemas.infragistics.com/xaml" x:Class="WpfApplication1.UserControl1" 
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
 
        <TabControl>
            <TabItem>
                <Grid>
                    <CheckBox>DEFAULT ITEMCheckBox>                 Grid>             TabItem>             <TabItem>                 <ig:XamMultiColumnComboEditor />             TabItem>         TabControl>     Grid> UserControl>