Bizarre WPF Template Rerendering - wpf

Question

My WPF application is employing the MVVM pattern, where the views are discovered using WPFs type-based DataTemplate mechanism.
I have one View that contains a ListBox, and the DataTemplate for the ViewModel type in the ListBox is in a Resource on the Grid that contains the ListBox.
In this DataTemplate, I have a custom Button class that has a DependencyProperty that is bound to a string property on the underlying ViewModel. When the Button is clicked, code-behind in the custom Button class gets the value out of the DependencyProperty and passes it in to a modal dialog, gets the edited value back from the dialog and updates the DependencyProperty (which then flows, through binding, back into the ViewModel). This whole process works fine.
However, the very first time this happens, something in the rendering of the dialog causes WPF to do something which results in the items in the ListBox being re-rendered. As a result of this, the actual Button that was clicked is detached from the Visual Tree, and the object being bound to is "disconnected". This only happens the very first time the dialog is evoked during the run of the application. Once it happens, everything is fine until you restart the application.
I'm at a loss. My best guess (based on the call stack for the constructor of my custom Button) is that something is causing WPF to recompile the resources for my application (or, at least, this one View), but I can't imagine what, nor how to prevent it (or force it to happen during startup).
Any suggestions would be awesome. Thanks!
David Mullin
IMA Technologies
Edited: Here's an attempt to show what the code looks like (boiler plate code omitted)
<Grid>
<Grid.Resources>
<DataTemplate DataType="{x:Type ct:RecordDisplayDataSourceAuthoringViewModel}">
<ctConfigControls:SetInfoButton Info="{Binding AutoNewSetInfoXml.Value}" Content="Set Info" />
</DataTemplate>
</Grid.Resources>
<!-- The DataSources property contains a list of RecordDisplayDataSourceAuthoringViewModel -->
<ListBox Grid.Row="1" ItemsSource="{Binding Path=DataSources}" />
</Grid>
public class SetInfoButton : Button
{
public static readonly DependencyProperty InfoProperty = DependencyProperty.Register("Info", typeof(string), typeof(SetInfoButton),
new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
public string Info
{
get { return (string)GetValue(InfoProperty); }
set { SetValue(InfoProperty, value); }
}
public SetInfoButton()
{
Click += new RoutedEventHandler(SetInfoButton_Click);
Focusable = false;
}
void SetInfoButton_Click(object sender, RoutedEventArgs e)
{
string info = Info;
if (SetInfoDialog.Show(VisualTreeHelperEx.FindVisualAncestor<Window>(this), ref info) == true)
{
Info = info;
}
}
}
public partial class SetInfoDialog : DialogWindow, IDesignerDataSource
{
public static bool Show(Window parent, ref string info)
{
SetInfoDialog dlg = new SetInfoDialog(info);
dlg.Owner = parent;
if (dlg.ShowDialog() == true)
{
info = dlg.RawInfo;
return true;
}
return false;
}
public SetInfoDialog(string rawInfo)
{
//...
}
}
<ct:DialogWindow x:Class="CaseTrakker.Windows.Dialogs.SetInfoDialog">
<ct:DialogWindow.Buttons>
<ct:ImageButton Image="{DynamicResource {x:Static ct:Common.OkImageKey}}" Content="_Ok" Click="Ok_Click" />
<ct:ImageButton Image="{DynamicResource {x:Static ct:Common.CancelImageKey}}" Content="_Cancel" Click="Cancel_Click" IsCancel="True" />
</ct:DialogWindow.Buttons>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid Grid.Row="0" Grid.Column="0" Visibility="{Binding Path=HideObjectSelectorControls, Converter={StaticResource InvertedBoolToVisibilityConverter}}" >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Label Grid.Row="0" Grid.Column="0">System Object</Label>
<ct:SystemObjectComboBox Grid.Row="0" Grid.Column="1" CreateOnly="True" SelectedValue="{Binding Path=SystemObjectNumber}" />
<Label Grid.Row="1" Grid.Column="0">Type</Label>
<ctConfigControls:TemplateComboBox Grid.Row="1" Grid.Column="1"
SystemObject="{Binding Path=SystemObjectNumber, Converter={StaticResource IntToStandardSystemObjectConverter}}"
SelectedValue="{Binding Path=TemplateId}" />
</Grid>
<Button Grid.Row="0" Grid.Column="1" Click="Import_Click">Import</Button>
<Grid Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<StackPanel Grid.Column="0" Orientation="Vertical" Margin="4,8,4,4"
Visibility="{Binding Path=DisplayText, Converter={StaticResource EmptyToVisibilityConverter}}">
<Label FontWeight="Bold">Notes</Label>
<TextBox Text="{Binding Path=DisplayText, Mode=OneWay}" IsReadOnly="True"/>
</StackPanel>
<ctConfigDesigner:DataDesigner x:Name="Designer" Grid.Column="1" Loaded="DataDesigner_Loaded" />
</Grid>
</Grid>
</ct:DialogWindow>
<Style x:Key="DialogWindowStyle" TargetType="{x:Type ctWindows:DialogWindow}" BasedOn="{StaticResource {x:Type Window}}">
<Setter Property="Background" Value="{DynamicResource {x:Static ctThemes:Common.StandardWindowBackgroundBrushKey}}" />
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<Grid>
<Grid.LayoutTransform>
<ScaleTransform x:Name="ZoomFrame"
ScaleX="{Binding Path=ZoomValue, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}"
ScaleY="{Binding Path=ZoomValue, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}"/>
</Grid.LayoutTransform>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid Grid.Row="0" Grid.Column="0">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Image Grid.Row="0" Grid.Column="0" Height="35" Width="35"
Visibility="{Binding Path=HasTitleImage, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}, Converter={StaticResource BoolToVisibilityConverter}}"
Source="{Binding Path=TitleImage, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}" />
<Label Grid.Row="0" Grid.Column="1" Content="{Binding Path=Title, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}"
Style="{DynamicResource LabelTitle}" FontWeight="Bold" />
<ContentControl Grid.Row="0" Grid.Column="2"
DataContext="{Binding Path=DataContext, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}"
Content="{Binding Path=HeaderContent, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}" />
</Grid>
<ContentControl Grid.Row="1" Grid.Column="0"
DataContext="{Binding Path=DataContext, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}"
Content="{Binding Path=WindowContent, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}" />
<ContentControl Grid.Row="2" Grid.Column="0"
DataContext="{Binding Path=DataContext, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}"
Content="{Binding Path=ButtonPanel, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ctWindows:DialogWindow}}}" />
</Grid>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>