In WPF XAML how can I concatenate 2 constants so I can use pre-define paths?

Question

I'm new to XAML, so presume I'm missing something simple. I want to replace the path part of the source path with a c# constant for easier path management, for example I have:

<Image Source="/Images/Themes/Buttons/MyPicture.png" />

and in another class I have my constant defined:

public static readonly string UriImagesButtons = "/Images/Big/PNG/";

I want to have something along the lines of:

<Image Source="{static:UriImagesButtons + MyPicture.png}" />

This means that I can change the path globally at a stroke if the need arises. What's the syntax to do this?

Answer 1

Replacing the path means that you have to do a data binding... So why don't you save in your C# class the full file path and bind to it?

Answer 2

You should take a look at the discussion on this thread: string manipulation in xaml attribute

Basically, you can create your own markup extension that takes 2 parameters and concatenates them. This particular example is also used for binding. I suspect you'd like to be able to bind to where you have the root path defined, or some other data perhaps.

Answer 3

The easiest way to do this is with a MultiBinding with a StringFormat:

<Path>
    <Path.Source>
        <MultiBinding StringFormat="{}{0}{1}">
            <Binding Mode="OneTime" Source="{x:Static lcl:ConstantOwner.UriImagesButtons}" />
            <Binding Mode="OneTime" Source="MyPicture.png" />
        </MultiBinding>
    </Path.Source>
</Path>

In the StringFormat parameter, you have to escape the first curly brace with a "{}" so the XAML parser doesn't think it is a markup extension.