how to get base uri of referencing xaml in a custom control

Question

I have an custom control, which has an Image element with its Source property exposed to user, like this

<ControlTemplate>
    <Image x:Name="PART_Image" Source="{Binding ImageUri, RelativeSource={RelativeSource TemplatedParent}}"/>
</ControlTemplate>

where ImageUri is an property in the control class, like this

public Uri ImageUri { get; set; }

this custom control is in an assembly customcontrol.dll , I can reference and use this control in an exe with no problem, like this

<cc:MyControl ImageUri="/Resources/Image.png" />

where Image.png is a resource of the exe project.

but if I reference and use this control in an dll assembly, there is a problem, I have to use a absolute "pack://..." uri to reference an image in the calling dll, if I use an relative uri like "Resources/Image.png", the resource cant be loaded, it turns out, when this uri is applied on the Image element, it resolves the relative uri from customcontrol.dll, not the calling dll assembly, so I want to do this:

public Uri ImageUri {
    get { ...... }
    set {
        if (!value.IsAbsolute) {
            // Get the assembly name of parent xaml file or code
            // and construct a "pack://" uri from the assembly name
            // and value.OriginalString, but how ??????
        }
    }
}

How can I get the assembly of the xaml code that uses my custom control ? if the control is used in code maybe I can use GetCallingAssembly in my methods, but xaml stuff is called from PresontationCore.dll, how can I find out the xaml assembly ???

Answer 1

OK I have found a solution myself. I should implement IUriContext interface, which has only one property: Uri BaseUri, this is exactly what I want.