Creating DLL that contains a ResourceDictionary

Question

I have created a new WPF-Project. After creating the project, I changed the project properties to outputtype = classlibrary.

Here is my file structure:

The CustomWindow.xaml is a ResourceDictionary which discribes the appearance of the CustomWindow.cs. The file CustomWindow.xaml looks like

<ResourceDictionary x:Class="WpfApplication1.CustomWindow"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:options="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options"
  xmlns:sys="clr-namespace:System;assembly=mscorlib">

  <Style x:Key="MainWindow" TargetType="{x:Type Window}">
     <Setter Property="Template">
         <!-- ... -->  
     </Setter>
  </Style>
</ResourceDictionary>

The class CustomWindow.xaml looks like

namespace WpfApplication1
{
    public partial class CustomWindow : ResourceDictionary
    {
        public CustomWindow()
        {
            InitializeComponent();
        }
    }
}

Now I added to the App.xaml following

<Application x:Class="WpfApplication1.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <!-- Common base theme -->
                <ResourceDictionary Source="pack://application:,,,/WpfApplication1;component/CustomWindow.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

I changed the property buildprocess of the file CustomWindow.xaml to Page.

After that I build the lib. Now I want to use the style MainWindow for my new project's main window. I've added the lib to the project references. And to the App.xaml I added some lines of code:

<Application x:Class="WpfApplication2.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>
                <!-- Common base theme -->
                <ResourceDictionary Source="pack://application:,,,/WpfApplication1;component/CustomWindow.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>

I tried to build it, but I become two error's. The first

The resource "MainWindow" couldn't be find.

The second

An error occurred while finding the resource dictionary "pack://application:,,,/WpfApplication1;component/CustomWindow.xaml".

Maybe someone of you got an idea.

Answer 1

1. Create a new WPF User Control Library project in Visual Studio.
2. Add a new ResourceDictionary to this project where you define your window style.
3. Add a reference to the WPF User Control Library Project from your WPF application project.

4. Modify the App.xaml file in the WPF Application project:

   <Application x:Class="WpfApplication2.App"
                    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:local="clr-namespace:WpfApplication1"
                    StartupUri="Window9.xaml">
       <Application.Resources>
           <ResourceDictionary>
               <ResourceDictionary.MergedDictionaries>
                   <!-- Common base theme -->
                   <ResourceDictionary Source="pack://application:,,,/WpfControlLibrary1;component/CustomWindow.xaml" />
               </ResourceDictionary.MergedDictionaries>
           </ResourceDictionary>
       </Application.Resources>
   </Application>
   

"WpfControlLibrary1" is the name of the WPF User Control Library in the sample markup above and "CustomWindow" is the name of the resource dictionary in this project.

5. Set the Style property of your MainWindow in the WPF Application like this:

   <Window x:Class="WpfApplication2.MainWindow"
           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
           xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
           xmlns:local="clr-namespace:WpfApplication2"
           mc:Ignorable="d"
           Title="MainWindow" Height="350" Width="525" Style="{StaticResource MainWindow}">
       <Grid>
   
       </Grid>
   </Window>