UserControl does not assume height of parent container

[ausadmin]

I have been struggling with this issue for some time, and I have now constructed a simple example to demonstate the problem. I am not sure whether this is an issue with WPF or my lack of understanding. As part of our application, I have created a wizard along the lines of Creating an Internationalized Wizard in WPF. This uses the MVVM pattern and the various pages of the wizard are implemented in User Controls. The problem that I have is when the wizard window is resized, the UserControl does not take the height of the window. However it does take the width of the window. The result is that controls such as a list box, which the user may need to have resize with the window, do not resize. I have removed the complexity of our app, and created a very simple example with a window, that just contains a HeaderedContentControl, which contains the model for the UserControl. The window is

<Window x:Class="Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:UserControlDemo"
Title="Window1" Height="300" Width="300">
<Window.Resources>
<DataTemplate DataType="{x:Type local:SimpleUserControlModel}">
<local:SimpleUserControl />
</DataTemplate>
</Window.Resources>
<Grid>
<HeaderedContentControl Name="hcControl" Margin="20" Content="{x:Type local:SimpleUserControl}"
Height="auto" Width="auto" VerticalContentAlignment="Stretch" />
</Grid>
</Window>

Window code:

Class Window1
Private _simpleModel As SimpleUserControlModel

Public Sub New()

    ' This call is required by the Windows Form Designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.
    \_simpleModel = New SimpleUserControlModel
    hcControl.Content = \_simpleModel
End Sub

End Class

User control:

<UserControl x:Class="SimpleUserControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
<Grid>
<Border Margin="5" BorderThickness="5" BorderBrush="Red" />
</Grid>
</UserControl>

User control model:

Public Class SimpleUserControlMod

[Mark Salsbery]

The default template for a HeaderedContentControl is

<ControlTemplate TargetType="{x:Type HeaderedContentControl}">
    <StackPanel>
        <ContentPresenter ContentSource="Header"/>
        <ContentPresenter />
    </StackPanel>
</ControlTemplate>

which gives you the behavior you're seeing, because they used a StackPanel. I would use a grid in the HeaderedContentControl template instead. Here's an example (simplifying your example even more):

<Window.Resources>
    <Style x:Key="HeaderedContentControlStyle1" TargetType="{x:Type HeaderedContentControl}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type HeaderedContentControl}">
                    <Grid>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto" />
                            <RowDefinition Height="\*" />
                        </Grid.RowDefinitions>
                        <ContentPresenter Grid.Row="0" ContentSource="Header"/>
                        <ContentPresenter Grid.Row="1" />
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Window.Resources>

<Grid>
    <HeaderedContentControl Name="hcControl" Margin="20" Style="{DynamicResource HeaderedContentControlStyle1}" >
        <Grid>
            <Border Margin="5" BorderThickness="5" BorderBrush="Red" />
        </Grid>
    </HeaderedContentControl>
</Grid>

Mark Salsbery Microsoft MVP - Visual C++ :java:

modified on Tuesday, May 19, 2009 12:48 PM

[ausadmin]

Mark, Thanks for the simple solution to this problem! I can see now that I needed to have a style with a control template to define the behaviour of the HeaderedContentControl. Reading the help page again, I can see I missed "A HeaderedContentControl has a limited default style. An application developer can create a HeaderedContentControl, but its appearance will be very simple." Note that we need to use a UserControl, to represent a number of more complex "pages", which are swapped in / out in code as the user steps through the wizard. That is why we need the user control rather than the simpler approach you presented. I will implement this back in our application and hopefully it will solve the original problem. Regards, Tim

[Mark Salsbery]

ausadmin wrote:

That is why we need the user control rather than the simpler approach you presented.

Right, I figured that. I just wrapped it all into simple XAML so you could copy/paste it and try it out. The key point was the custom template :)

Mark Salsbery Microsoft MVP - Visual C++ :java:

[mick codeproject]

Thank you for saving my day!