How to use Data Trigger to Conditionally format a text block - wpf

Question

I need to conditionally change a TextBlock binding based on the value of an object which is one of many in an OC in my ViewModel. Im sure I need to use DataTriggers to accomplish this. Specifically I want to dynamically change the property that the first TexBlock below binds to for its Text Property. The OC Summary contains a collection of Name objects and each object has a Property called NameType. If NameType = 1 I want to bind to Name1, NameType=2 bind to Name2 etc. The second TextBlock is fine the way it is as it shows an associated value.
<ItemsControl Grid.Row="1" ItemsSource="{Binding Summary}" Margin="0,3,0,0">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock Style="{StaticResource TooltipLeftColumnTextStyle}" Text="{Binding Name}" />
<TextBlock Style="{StaticResource TooltipRightColumnTextStyle}" Text="{Binding Value}" />
<Border Grid.Row="1" Style="{StaticResource TooltipSeparatorBorder}" />
<Border Grid.Row="2" Style="{StaticResource TooltipSeparatorAlternateBorder}" />
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>

Answer 1

Something like this might work for you:
<ItemsControl Grid.Row="1" ItemsSource="{Binding Summary}" Margin="0,3,0,0">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock x:Name="TheTextBlock" Style="{StaticResource TooltipLeftColumnTextStyle}" Text="{Binding Name}" />
<TextBlock Style="{StaticResource TooltipRightColumnTextStyle}" Text="{Binding Value}" />
<Border Grid.Row="1" Style="{StaticResource TooltipSeparatorBorder}" />
<Border Grid.Row="2" Style="{StaticResource TooltipSeparatorAlternateBorder}" />
</Grid>
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding NameType}" Value="1">
<Setter TargetName="TheTextBlock" Property="Text" Value="{Binding Name1}"/>
</DataTrigger>
<DataTrigger Binding="{Binding NameType}" Value="2">
<Setter TargetName="TheTextBlock" Property="Text" Value="{Binding Name2}"/>
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Otherwise, the other option is to control the value of the bound Name in the ViewModel so that Name returns the value you want. When NameType changes, you would raise the PropertyChanged event with the parameter "Name" on the view model so that the UI becomes aware of the text change.

Answer 2

What you are looking for is a DataTemplateSelector, this will allow you to swap out the template based on the value of the object (or a property on that object) that is being passed in.
There are lots of better examples on the web than I can give here but this should get you started..
http://tech.pro/tutorial/807/wpf-tutorial-how-to-use-a-datatemplateselector
http://msdn.microsoft.com/en-us/library/system.windows.controls.datatemplateselector.aspx
http://breakingdotnet.blogspot.co.uk/2012/05/data-template-selector-in-xaml.html