Get height of header of a ListView with GridView - wpf

Question

How can I get the height of the header of a ListView with a GridView? Is it even possible?
I need to set the height of one control based on the height of the header of a ListView so I started writing a Converter. The problem is that I can't access the actual height.
The debugger of Visual Studio shows me that GridView has a property called HeaderRowPresenter, which in turn has a property ActualHeight. But I can't access it, HeaderRowPresenter seems to be protected or private.
All other ColumnHeader* properties (ColumnHeaderContainerStyle, ColumnHeaderTemplate, etc.) are null on this object, same for all Header* properties on the Columns (except for the String that is the content of the header).
Btw: I'm trying to solve a different problem and my current approach let me to this, so maybe I'm taking this on the wrong way.

Answer 1

Okay, I've found a solution but I'm not very proud of it, because it uses reflection:
I wrote a Converter that takes a View and a ListView as value and parameter and returns the height difference of the headers:
public class HeightSyncConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
GridView gvLocal = value as GridView;
ListView lvOther = parameter as ListView;
if( gvLocal == null || lvOther == null)
{
return 0;
}
GridView gvOther = (GridView)lvOther.View;
try
{
// get the non-public HeaderRowPresenter property
GridViewHeaderRowPresenter hrpLocal = (GridViewHeaderRowPresenter)gvLocal.GetType().GetProperty("HeaderRowPresenter", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(gvLocal);
GridViewHeaderRowPresenter hrpOther = (GridViewHeaderRowPresenter)gvOther.GetType().GetProperty("HeaderRowPresenter", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(gvOther);
if( hrpLocal == null || hrpOther == null )
{
return 0;
}
// Only works if the other ListView's header is higher than the local one's
if( hrpLocal.ActualHeight > hrpOther.ActualHeight )
{
return 0;
}
return hrpOther.ActualHeight - hrpLocal.ActualHeight;
}
catch(TargetInvocationException) { }
return 0;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return null;
}
}
I then use it to define the height of a Grid.Row:
<UserControl x:Class="GUI.ListViewLayout"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:GUI"
xmlns:conv="clr-namespace:GUI.Converter"
mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="300"
Loaded="Window_Loaded">
<UserControl.Resources>
<Style x:Key="verticalGridViewColumnHeader" TargetType="GridViewColumnHeader">
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<TextBlock Text="{Binding}" FontWeight="Bold"
VerticalAlignment="Center" TextAlignment="Center" HorizontalAlignment="Center">
<TextBlock.LayoutTransform>
<RotateTransform Angle="270" />
</TextBlock.LayoutTransform>
</TextBlock>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
<conv:HeightSyncConverter x:Key="myConverter" />
</UserControl.Resources>
<Grid x:Name="grid">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="150" />
<ColumnDefinition Width="150" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition x:Name="fillerRow" Height="{Binding View, ElementName=listView1, Converter={StaticResource myConverter}, ConverterParameter={x:Reference listView2}}" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Button x:Name="someControl" Grid.RowSpan="2">Placeholder</Button>
<ListView x:Name="listView1" Grid.Row="2">
<ListView.View>
<GridView>
<GridViewColumn Header="Header 1" Width="60"/>
<GridViewColumn Header="Header 2" Width="60" />
</GridView>
</ListView.View>
</ListView>
<ListView x:Name="listView2" Grid.Row="1" Grid.Column="1" Grid.RowSpan="2">
<ListView.View>
<GridView>
<GridViewColumn Header="Long Header 1"
HeaderContainerStyle="{StaticResource verticalGridViewColumnHeader}" Width="Auto" />
<GridViewColumn Header="Long Header 2"
HeaderContainerStyle="{StaticResource verticalGridViewColumnHeader}" Width="Auto" />
</GridView>
</ListView.View>
</ListView>
</Grid>
</UserControl>
The problem is that the converter is called before the ListViews and their headers are initialized, so I reevaluate the Binding in the code-behind:
public partial class ListViewLayout : UserControl
{
public ListViewLayout()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
BindingExpression binding = fillerRow.GetBindingExpression(RowDefinition.HeightProperty);
binding.UpdateTarget();
}
}
All in all, I don't think this is worth the effort and the best way is to define the height of the headers myself instead of retrieving an automatically calculated ActualHeight.