dynamically nest DataTemplates in ListView

Question

I have an object of Type MyTypeOneViewModel that is displayed in the first column of ListView and I have an object of Type MyTypeTwoViewModel that is displayed in the 2nd column of my ListView. Both types have a property of type MyNestedViewModel. Now I would like to display a different DataTemplate for each cell in the ListView depending on the actual Type of that Property. For example if the property actually holds a MyDoubleNestedViewModel I want to display a Textbox in that cell and if that property holds a MyBooleanNestedViewModel I want to display a ComboBox in that particular cell of the ListView. Note that The DataTemplate could vary in each row and column.

Can I achieve this without a TemplateSelector? WPF is able to autmatically chose the right DataTemplate based on the bound Type. But does that work in this nested scenario in a ListView too somehow?

Answer 1

Consider these options:

1. Bind directly to the sub-property.

Bind the column to the sub-property (of type MyNestedViewModel) rather than the parent. WPF will then pick a template based on the type of the nested view model, rather than the type of the parent view model.

<GridViewColumn DisplayMemberBinding="{Binding TheChildViewModel}"/>

2. Include a ContentControl in your cell template.

In your grid column templates, bind a ContentControl to the child property:

<GridViewColumn.CellTemplate>
    <DataTemplate>
        <StackPanel>
            <Label Content="{Binding SomePropertyOnParentViewModel}"/>
            <ContentControl Content="{Binding TheChildViewModel}"/>
        </StackPanel>
    </DataTemplate>
</GridViewColumn.CellTemplate>

HTH, Kent

Answer 2

WPF can do exactly what you want.

Reference the assembly that has your data types and add a DataTemplate resource for each type you need to display.

 xmlns:ui="clr-namespace:YourAssembly"
    <Window.Resources>

        <DataTemplate DataType="ui:MyDoubleNestedViewModel ">
              <Grid Margin="5,5,5,5" >

                   <TextBlock Text="{Binding Path=Value}"/>              
        </Grid>

        </DataTemplate>

        <DataTemplate DataType="ui:MyBooleanNestedViewModel ">
              <Grid Margin="5,5,5,5" >

                   <ComboBox ItemsSource="{Binding Path=Items}"/>                
        </Grid>

        </DataTemplate>
    </Window.Resources>

Now this template will be used with any list or content control in this window that’s bound to your view model objects. You don’t need to specify the ItemTemplate setting.