Using app.xaml and ResourceDictionaries for Cleaner WPF Customisation

When I first started making WPF forms, I was using PowerShell. This was a good starting point I think as I felt really comfortable with PowerShell which let me experiment more freely and break things in a way that I still felt comfortable.

However, this also meant putting all of my XAML into a single string. This might not sound too bad, but when you have five buttons all with slightly different templates and behaviours, the code quickly becomes messy and hard to read. Note that XAML is easy to read in the first place 😫 I was no stranger to having code that looked like this:

<Border Grid.Column="0" Grid.Row="1" Background="#FFE87E31" HorizontalAlignment="Right" Width="25" Height="25" Margin="0,0,2,0" CornerRadius="20"  BorderBrush="White" BorderThickness="1">
                <Label Name="Search_Button" Cursor="Hand" Foreground="White" Content="🔍" FontSize="12" Width="25" Height="27" Margin="-1.667,-1.667,-0.334,-0.334" />
            <Border HorizontalAlignment="Stretch" Grid.Column="0" Grid.Row="2" VerticalAlignment="Stretch" Background="#FF34495F" >
                <ScrollViewer VerticalScrollBarVisibility="Auto">
        <!-- ALL OPTION OBJECTS HERE -->
                        <Border Height="35">
                                    <Setter Property="Border.Background" Value="#FF34495F"/>
                                        <Trigger Property="Border.IsMouseOver" Value="True">
                                            <Setter Property="Border.Background" Value="#FF1F2A36" />
                            <Label Name="General_Information_Button" Cursor="Hand" VerticalContentAlignment="Center" Foreground="White" Content="General Information" FontFamily="Century Gothic" FontSize="14" />

Horrible I know…

But when I moved to use C# with WPF, I found that I could have separate resources that could be used by multiple controls at the same time. You do this by adding a resource dictionary to the app.xaml file inside the WPF project.

Here is a quick example of what I mean. I created a Styles folder in the root of my WPF project and added a new ResourceDictionary(WPF). I called this resource dictionary “TextStyles” and it looks like this:

<ResourceDictionary xmlns=""
    <Style TargetType="{x:Type TextBlock}">
        <Setter Property="FontFamily" Value="Arial"/>
        <Setter Property="FontSize" Value="28"/>
        <Setter Property="FontWeight" Value="Bold"/>
        <Setter Property="Foreground" Value="White"/>

Perfect, I then added this to my app.xaml file which now looks like this:

<Application x:Class="WPFUI.App"
                <ResourceDictionary Source="/Styles/TextStyles.xaml"/>

From now on, all the text blocks in the WPF application would use the Arial font, use font size 28, be bold and also be white.

Important Notes:

  1. It’s important to add your resource dictionaries to the app.xaml file in the correct order. You want to work from top to bottom. Meaning you don’t want a resource dictionary using something from another resource dictionary below it. For example, if you are using custom colours and want your text blocks to be that colour, you would put your colour resource first and then your text block resource.
  2. If you don’t want a resource to be used everywhere in your application if you style inside the resource dictionary a name. Then you can reference the style inside your WPF XAML code.


Setting Up Caliburn.Micro MVVM

This is a fairly lengthy post that shows how to set up an initial MVVM WPF form using Caliburn.Micro.

Let’s get started, we’ll open up Visual Studio and chose to create a new WPF:

Visual Studio -> New Project -> WPF App (.Net Framework)

I usually set the project name to something like WPFUI and my solution name to be something like MVVMProject or the actual product name. For example, Microsoft might use Microsoft Outlook. Probably not, but you get what I’m saying…



First I will add Caliburn.Micro to my project. To do this go to Solution Explorer -> References -> Add NuGet Packages and search for Caliburn.Micro:



Now we can delete the MainWindow.xaml



Create a Views and ViewModels folder. This is where your viewmodels and views will call home.



Create a new class in the ViewModels folder and call it ShellViewModel and make it public. You’ll also want to inherit from screen and add the using statement for Caliburn.Micro:


Create a new window in the Views folder and call it ShellView


Create a new class in the root directory called Bootstrapper and inherit from BootstrapperBase and add the using statement for Caliburn.Micro


In App.xaml remove the StartupUri element and add the bootstrapper class as a resource by adding:

            <local:Bootstrapper x:Key="Bootstrapper" />

Your app.xaml should look like this:



Now go back into your Bootstrapper class and add the following:

public Bootstrapper()
protected override void OnStartup(object sender, StartupEventArgs e)

You’ll also need to add a using statement for System.Windows and ProjectName.ViewModels.

The program should now launch and show an empty white screen with “ShellView” as the window’s title. This is the first entry into a hopefully long series into the world of Caliburn.Micro.

Enjoy! 😊