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ComboBox Content Issues with DisplayMemberPath

I have a ComboBox, and I set the combo.ItemsSource property to a List object. The Book class contains two properties: Abbreviation and Name.

I set the ComboBox DisplayMemberPath to " Abbreviation ", but the following style set to ComboBox does not display the Abbreviation property, but instead shows "Words". The book ", which is the name of the class. The ComboBox drop-down list displays the list correctly (using the specified Abbreviation property). The problem is the selected ComboBox element , which is displayed when the ComboBox drop-down list is closed.

I think the problem is in ContentPresenter in the DataTemplate, but I could not find a successful solution. Currently, the ContentPresenter Content property is set to Content = "{TemplateBinding Content}, but I don't know how it should be.

Any ideas on how to show the property specified in DisplayMemberPath on the selected item?

thanks

code:

<ControlTemplate x:Key="ComboBoxToggleButton" TargetType="ToggleButton"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition Width="20" /> </Grid.ColumnDefinitions> <Border x:Name="Border" Grid.ColumnSpan="2" CornerRadius="2" BorderThickness="1" Background="{DynamicResource ribbonTitleFade}" /> <Border Grid.Column="0" CornerRadius="2,0,0,2" Margin="1,6,1,6" BorderBrush="{DynamicResource boSecE}" BorderThickness="0,0,1,0" /> <Path x:Name="Arrow" Grid.Column="1" Fill="White" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 4 4 L 8 0 Z" /> </Grid> <ControlTemplate.Triggers> <Trigger Property="ToggleButton.IsMouseOver" Value="true"> <Setter TargetName="Border" Property="Background" Value="{DynamicResource ribbonTitleFade}" /> </Trigger> <Trigger Property="ToggleButton.IsChecked" Value="true"> <Setter TargetName="Border" Property="Background" Value="{DynamicResource ribbonTitleFade}" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="Border" Property="Background" Value="Black" /> <Setter TargetName="Border" Property="BorderBrush" Value="Black" /> <Setter Property="Foreground" Value="Gray"/> <Setter TargetName="Arrow" Property="Fill" Value="Gray" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> <Style x:Key="comboBoxBorderTransparent" TargetType="Control"> <Setter Property="BorderBrush" Value="{DynamicResource boPrimC}" /> </Style> <Style x:Key="comboItemStyle" TargetType="ComboBoxItem"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type ComboBoxItem}"> <Border x:Name="backBorder" > <StackPanel Orientation="Horizontal"> <Rectangle x:Name="rectA" Stroke="White" Width="4" Height="4" Fill="#80FFFFFF" Margin="5,0,0,0" HorizontalAlignment="Left" /> <TextBlock x:Name="text" Foreground="White" FontSize="10px"> <ContentPresenter Margin="8,1,0,1" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" /> </TextBlock> </StackPanel> </Border> <ControlTemplate.Triggers> <Trigger Property="ComboBoxItem.IsMouseOver" Value="true"> <Setter TargetName="rectA" Property="Stroke" Value="Black" /> <Setter TargetName="rectA" Property="Fill" Value="#80000000" /> <Setter TargetName="backBorder" Property="Background" Value="White"/> <Setter TargetName="text" Property="Foreground" Value="{DynamicResource boPrimC}"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> <DataTemplate x:Key="comboSelectedItemTemplate"> <TextBlock Foreground="White" FontSize="10px"> <ContentPresenter Content="{TemplateBinding Content}" /> </TextBlock> </DataTemplate> <Style TargetType="ComboBox"> <Setter Property="SnapsToDevicePixels" Value="true"/> <Setter Property="OverridesDefaultStyle" Value="true"/> <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/> <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/> <Setter Property="ScrollViewer.CanContentScroll" Value="true"/> <Setter Property="MinWidth" Value="60"/> <Setter Property="MinHeight" Value="20"/> <Setter Property="ItemContainerStyle" Value="{DynamicResource comboItemStyle}"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ComboBox"> <Grid> <ToggleButton Name="ToggleButton" Grid.Column="2" Template="{StaticResource ComboBoxToggleButton}" Focusable="false" IsChecked="{Binding Path=IsDropDownOpen,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press"> </ToggleButton> <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" Name="ContentSite" IsHitTestVisible="False" Content="{TemplateBinding SelectionBoxItem}" ContentTemplate="{DynamicResource comboSelectedItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Margin="3,3,23,3" /> <Popup Name="Popup" Placement="Bottom" IsOpen="{TemplateBinding IsDropDownOpen}" AllowsTransparency="False" Focusable="False" PopupAnimation="Slide"> <Grid Name="DropDown" SnapsToDevicePixels="True" MinWidth="{TemplateBinding ActualWidth}" MaxHeight="{TemplateBinding MaxDropDownHeight}"> <Border x:Name="DropDownBorder" Background="{DynamicResource ribbonTitleFade}" BorderThickness="1" BorderBrush="{DynamicResource boPrimC}" /> <ScrollViewer Margin="4,6,4,6" SnapsToDevicePixels="True"> <StackPanel IsItemsHost="True" KeyboardNavigation.DirectionalNavigation="Contained" /> </ScrollViewer> </Grid> </Popup> </Grid> <ControlTemplate.Triggers> <Trigger Property="HasItems" Value="false"> <Setter TargetName="DropDownBorder" Property="MinHeight" Value="95"/> </Trigger> <Trigger Property="IsEnabled" Value="false"> <Setter Property="Foreground" Value="Black"/> </Trigger> <Trigger Property="IsGrouping" Value="true"> <Setter Property="ScrollViewer.CanContentScroll" Value="false"/> </Trigger> <Trigger SourceName="Popup" Property="Popup.AllowsTransparency" Value="true"> <Setter TargetName="DropDownBorder" Property="CornerRadius" Value="2"/> <Setter TargetName="DropDownBorder" Property="Margin" Value="0"/> </Trigger> <Trigger Property="IsEditable" Value="true"> <Setter Property="IsTabStop" Value="false"/> <!--<Setter TargetName="ContentSite" Property="Visibility" Value="Hidden"/>--> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> <Style.Triggers> </Style.Triggers> </Style>
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3 answers

I think you want something similar in your ComboBox template:

 <ContentPresenter Content="{TemplateBinding ComboBox.SelectionBoxItem}" ContentTemplate="{TemplateBinding ComboBox.SelectionBoxItemTemplate}" ContentStringFormat="{TemplateBinding ComboBox.SelectionBoxItemStringFormat}" Margin="{TemplateBinding Control.Padding}" HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
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If your template does not explicitly handle the DisplayMemberPath value, the template will not use it to modify the ComboBoxItem . You will need to bind to the element directly in the ControlTemplate or use a separate DataTemplate .

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I found a problem with the BureauBlack theme, where it simply would not apply DisplayMemberPath , just showed the name of the object. I had a window with many (15+) ComboBoxes, and all but 2 worked correctly using DisplayMemberPath.

I removed the following from ContentPresenters and GridViewRowPresenters:

 Content="{TemplateBinding Content}" ContentTemplate="{TemplateBinding ContentTemplate}"

in ListBoxItem, ComboBoxItem, ListViewItem . It may need more correction, but that was all we found that we are using.

Using Microsoft.Net 4.0 Framework. I have not tried 4.5 or 3.5.

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