Using a tree view in Windows Forms is straightforward, but in WPF the control has undergone a lot of modifications. In this blog I’ll describe how to do some tasks that seem to be easy enough, and describe some caveats.

Scrollbar problem

This is the sample window (Don’t mind the colors, they’re just to show the point):

<Window x:Class=”FindInSvclog.MainWindow”
        xmlns=”http://schemas.microsoft.com/winfx/2006/xaml/presentation”
        xmlns:x=”http://schemas.microsoft.com/winfx/2006/xaml”
        Title=”MainWindow” Height=”350″ Width=”568″>
    <StackPanel>
        <Canvas Width=”500″ Height=”228″ Name=”searchCanvas”>
        </Canvas>
        <Grid Grid.Row=”1″>
            <Grid.RowDefinitions>
                <RowDefinition></RowDefinition>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width=”1*”></ColumnDefinition>
                <ColumnDefinition Width=”1*”></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <TreeView Background=”#FF00FF00″ Name=”FileTree” AlternationCount=”1″ />
            <GridSplitter Width=”5px” ResizeDirection=”Columns” Background=”DarkSlateGray”/>
            <TextBlock Grid.Column=”1″ Background=”#FF0000FF” />
        </Grid>
    </StackPanel>
</Window>

The highlighted TreeView doesn’t have a vertical scrollbar, even though it should.

The problem isn’t related to the TreeView, but to the StackPanel: In a StackPanel every item gets all the space it needs. So the StackPanel doesn’t report its current size back (this is the correct behavior!). Changing the StackPanel into a Grid solved the problem completely.