Question

I am trying to create a custom ItemsControl by directly inheriting from ItemsControl (WPF/Silverlight, I am using same code base for both). I have created an Item class for it by inheriting from ContentControl. I want to create IsSelected property for the Item class. I reflected the ListBoxItem class but am not very clear how IsSelected property is getting set.
Any suggestions/ pointers will be really helpful.

Answer 1

If you want an ItemsControl with no ListBox features except that it internally supports the concept of selection, you can easily create a lookless ListBox that is indistinguishable from an ItemsControl. Here are the two two side by side and you can’t tell the difference. The only difference is that the left list supports selection internally.

<Grid>
    <Grid.Resources>
        <x:Array Type="sys:String" x:Key="sampleData">
            <sys:String>Red</sys:String>
            <sys:String>Green</sys:String>
            <sys:String>Blue</sys:String>
        </x:Array>
    </Grid.Resources>
    <UniformGrid Columns="2">
        <ItemsControl ItemsSource="{StaticResource sampleData}"/>
        <ListBox ItemsSource="{StaticResource sampleData}">
            <ListBox.Style>
                <Style TargetType="ListBox">
                    <Setter Property="Focusable" Value="False"/>
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="ListBox">
                                <ItemsPresenter/>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </ListBox.Style>
            <ListBox.ItemContainerStyle>
                <Style TargetType="ListBoxItem">
                    <Setter Property="Focusable" Value="False"/>
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="ListBoxItem">
                                <ContentPresenter/>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </ListBox.ItemContainerStyle>
        </ListBox>
    </UniformGrid>
</Grid>

So the best advice is if you want selection, derive from ListBox and style away what you don’t want about it or at least derive from Selector.