Control inheritance and blendability - wpf

Question

I created a custom control which inherits from Window. The goal is to make a reusable window for all the small apps I'll program in my company, and not having to redo the header/footer/base styles... each time.
So here is what I did.
The class:
public class MyWindow : Window
{
public bool ShowHeader
{
get { return (bool)GetValue(ShowHeaderProperty); }
set { SetValue(ShowHeaderProperty, value); }
}
// Using a DependencyProperty as the backing store for ShowHeader. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ShowHeaderProperty =
DependencyProperty.Register("ShowHeader", typeof(bool), typeof(MyWindow), new PropertyMetadata(true));
public string HeaderText
{
get { return (string)GetValue(HeaderTextProperty); }
set { SetValue(HeaderTextProperty, value); }
}
// Using a DependencyProperty as the backing store for HeaderText. This enables animation, styling, binding, etc...
public static readonly DependencyProperty HeaderTextProperty =
DependencyProperty.Register("HeaderText", typeof(string), typeof(MyWindow), new PropertyMetadata(""));
public MyWindow()
{
this.Template = FindResource("MyWindowTemplate") as ControlTemplate;
}
}
The template:
<ControlTemplate x:Key="MyWindowTemplate" TargetType="{x:Type me:MyWindow}">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<DockPanel>
<Grid DockPanel.Dock="Top">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200" />
<ColumnDefinition Width="300" />
</Grid.ColumnDefinitions>
<Image Grid.Column="0" Source="Images/logo.gif" />
<TextBlock Grid.Column="1" Text="{TemplateBinding HeaderText}" />
</Grid>
<ContentPresenter />
</DockPanel>
</Border>
</ControlTemplate>
Those 2 things are in a class library.
In my app, I have set this.
app.xaml:
<Application x:Class="TestInheritance.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="MainWindow.xaml">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/ClassLibrary1;component/MyStyles.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>
and my MainWindow.xaml is:
<uc:MyWindow x:Class="TestInheritance.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:uc="clr-namespace:ClassLibrary1;assembly=ClassLibrary1"
Title="MainWindow"
Width="525"
Height="350"
HeaderText="Test1234"
ShowHeader="True">
<Grid>
<TextBlock Text="test text" />
</Grid>
</uc:MyWindow>
All of this works as intended in execution, but in the designer, I don't see the header (no matter the value I set for ShowHeader), neither the HeaderText.
What should I do to make all this "blendable", and see the header in the designer ?
EDIT
I tried moving the ControlTemplate in a style
<Style TargetType="{x:Type me:MyWindow}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type me:MyWindow}">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<DockPanel>
<Grid DockPanel.Dock="Top">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200" />
<ColumnDefinition Width="300" />
</Grid.ColumnDefinitions>
<Image Grid.Column="0" Source="Images/logo.gif" />
<TextBlock Grid.Column="1" Text="{TemplateBinding HeaderText}" />
</Grid>
<ContentPresenter />
</DockPanel>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
and use this
StyleProperty.OverrideMetadata(typeof(MyWindow), new FrameworkPropertyMetadata(FindResource(typeof(MyWindow))));
in Mywindow's constructor.
So now, I have the opposite, I see the header in design mode, but not in the application anymore...
EDIT2
I moved the style in Themes\Generic.xaml and added [assembly: ThemeInfo(ResourceDictionaryLocation.None, ResourceDictionaryLocation.SourceAssembly)] in the Assemblyinfo.cs of my class library.
I also added a static constructor to my class like this:
static MyWindow()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(MyWindow), new FrameworkPropertyMetadata(typeof(MyWindow)));
}
and it still doesn't work.
So now my solution structure is the following: (non-relevant parts omitted)
Solution
ClassLibrary1
Properties
AssemblyInfo.cs
Themes
Generic.xaml
MyWindow.cs
TestInheritance (the wpf app)
App.xaml
MainWindow.xaml
Edit3
Here is the link to my code: https://github.com/MerlinDuChaos/TestInheritance/

Answer 1

Set the default style in static constructor like this
static MyWindow()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(MyWindow), new FrameworkPropertyMetadata(typeof(MyWindow)));
}
Also dont forget to set this stupid little property:
<Style TargetType="{x:Type me:MyWindow}">
<Setter Property="Background" Value="White"/>
Try it out now
EDIT:
public partial class App : Application
{
//public App()
//{
// InitializeComponent();
// FrameworkElement.StyleProperty.OverrideMetadata(typeof(Window), new FrameworkPropertyMetadata
// {
// DefaultValue = FindResource(typeof(Window))
// });
//}
}
EDIT 2:
To force designer apply your custom window style you shall copy paste this inside app xaml.
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:/ClassLibrary1;component/Themes/Generic.xaml" />
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>