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Load external XAML file using LoadComponent

Answer 1

A:

You will need Absolute File URI including entire file://c:/ etc.. because Relative is used inside the application's resources only.

Akash Kava 2009-04-02 16:00:29

Now I get ArgumentException: Cannot use absolute URI.

alex2k8 2009-04-02 18:22:08

Answer 2

+1 A:

It seems that external XAML file can't be loaded by LoadComponent.

I checked the source code:

    public static void LoadComponent(Object component, Uri resourceLocator) 
    {
        ...

        // Passed a relative Uri here.
        // needs to resolve it to Pack://Application.
        //..\..\ in the relative Uri will get stripped when creating the new Uri and resolving to the 
        //PackAppBaseUri, i.e. only relative Uri within the appbase are created here
        Uri currentUri = new Uri(BaseUriHelper.PackAppBaseUri, resourceLocator); 

        ...
    }

So the resourceLocator SHOULD be a relative path. And it will be treated under application:/// authority.

MSDN

WPF supports two authorities: application:/// and siteoforigin:///. The application:/// authority identifies application data files that are known at compile time, including resource and content files. The siteoforigin:/// authority identifies site of origin files.

Possible data files are:

Packages and parts are analogous to applications and files, where an application (package) can include one or more files (parts), including:
Resource files that are compiled into the local assembly.
Resource files that are compiled into a referenced assembly.
Resource files that are compiled into a referencing assembly.
Content files.
Site of origin files.

The first 4 files are accessible with application://, but I am looking for external files, so the only option is "Content file".

So I turned app.xaml into content file (details are here)

Build Action to Content
Copy to Output Directory to Copy always
[assembly: AssemblyAssociatedContentFile("app.xaml")]

As result such exception was thrown: 'application/xaml+xml' ContentType is not valid.

    public static void LoadComponent(Object component, Uri resourceLocator) 
    {
        ...

            if (!MimeTypeMapper.BamlMime.AreTypeAndSubTypeEqual(contentType)) 
            {
                throw new Exception(SR.Get(SRID.ContentTypeNotSupported, contentType)); 
            }
        ...
    }

So the LoadComponent expects 'application/baml+xml' instead of 'application/xaml+xml'.

I don't know a way to store xaml as external file in 'application/baml+xml', so assume the task has no solution.

alex2k8 2009-04-02 20:13:24

The latest research shows that having BAML we can load it. Will change response latter.

alex2k8 2009-04-03 03:58:38

Answer 3

A:

I got this to work. My specific goal was to load a ResourceDictionary into the App class so I could have custom skins loaded from raw XAML files. Here's how. First, in App.xaml, Add the following:

    protected override void OnStartup(StartupEventArgs e) {
        base.OnStartup(e);
        LoadSkin("Skins/Skin1.xaml");

    }

    private void LoadSkin(string FilePath) {
        XmlReader XmlRead = XmlReader.Create(FilePath);
        Application.Current.Resources = 
            (ResourceDictionary)XamlReader.Load(XmlRead);
        XmlRead.Close();
    }

Create a "bin\Debug\Skins" folder and added a "Skin1.xaml" with the following content:

<ResourceDictionary 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>
    <Style x:Key="ButtonAStyle" TargetType="{x:Type Button}">
        <Setter Property="Control.Background" Value="Green" />
        <Setter Property="Control.Foreground" Value="White" />
    </Style>
</ResourceDictionary>

Specific to Skins

In this particular case, you have to make sure you are using the style resources correctly in your individual windows. Here's an example:

<Button 
    Name="button1" 
    Style="{DynamicResource ButtonAStyle}" 
    Click="button1_Click"
>Button</Button>

Here's a neat trick to try. In button1_Click(), try adding the same code you did in App.OnStartUp() above but with "Skin2.xaml" with "Red" as the background color for your buttons. The skin changes instantly without requiring a reload of the app or window.

Jim Carnicelli 2009-09-23 21:08:42

1. What is your VS version? I don't see such build action "Content Copy to Output" in VS2008? 2. Are you sure that Skin1.xaml is ONLY copied, and not compiled into .exe as a resource?

alex2k8 2009-09-24 11:51:14

I'm using VS 2008. Looks like I fooled myself, though. This works for me if I set "Build Action" to "Content". If I just put loose files in bin\Debug\Skins\, it doesn't work. :-P I'm looking for a fix now.

Jim Carnicelli 2009-09-25 14:23:14

Fixed. The key was using a XamlReader instead of Application.LoadComponent(). I've updated the code here to reflect it.

Jim Carnicelli 2009-09-25 14:51:28

Unfortunately, XamlReader.Load will work only for xaml files with out events in it

amazedsaint 2009-10-30 06:13:30

Answer 4

A:

In order for LoadComponent to work on an XAML resource, it will need to have a build action of "Page". Then the LoadComponent works, even in a Console app.

This could be useful when wanting to access sample data generated from Blend in a server app.

Wolfgang Grinfeld 2010-01-28 15:57:19

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Load external XAML file using LoadComponent

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