Why do some WPF binding fail against IronRuby properties?

Question

So, lets say I have two nearly identical classes in C# and Ruby:

C#

public class Test
{
    public Test()
    {
        ImageLocation = "http://www.ironruby.net/@api/deki/site/logo.png";
    }

    public string ImageLocation { get; set; }
}

Ruby

class Test
    attr_accessor :ImageLocation

    def initialize
      @ImageLocation = "http://www.ironruby.net/@api/deki/site/logo.png"
    end
end

When I bind to the "ImageLocation" property in C#, all three controls bind properly. When I bind to the same property with the IronRuby object, it works for TextBlock, but fails for TextBox and Image. Here is my XAML:

<Image Source="{Binding ImageLocation}" Width="50" />
<TextBlock Text="{Binding ImageLocation}" />
<TextBox Text="{Binding ImageLocation}" />

Why does the binding work properly for one control, but not the others?

score 1 · Answer 1 · 2010-07-31T17:25:34.553

1

~~Ivan Porto Carrero's book IronRuby in Action provides the solution to your problem. See databinding.rb from the book's source code.~~

This definitely doesn't solve the problem you're having, and I've repro'd it myself.

Update: Shay's answer worked for me, too.

edited Jul 31 '10 at 17:25

answered Jul 31 '10 at 01:39

I'm not clear to what the 'solution' is. I see that he is solving the `PropertyNotify` problem... but I don't see how he solves the binding problem I am having. I fully expect that all three controls in my XAML should be populated on start-up... without a change notification. Unfortunately, this is not happening. – Brian Genisio Jul 31 '10 at 02:10
Yeah, I just noticed that. I am trying to determine whether you may have discovered a name-mangling bug in IronRuby. – Jul 31 '10 at 02:12
@Brian: Sorry for answering the wrong question. I'll try to attach a test converter and see what, if anything, _is_ binding. – Jul 31 '10 at 02:53

score 1 · Accepted Answer · answered Jul 31 '10 at 05:29

1

IronRuby types have a few problems with WPF binding... let's say that it's not perfect yet :)

To solve your problem, I recommend you to use CLR classes and types. For example, to make your sample code work just convert this line:

@ImageLocation = "http://www.ironruby.net/@api/deki/site/logo.png"

To this:

@ImageLocation = "http://www.ironruby.net/@api/deki/site/logo.png".to_clr_string

answered Jul 31 '10 at 05:29

Shay Friedman

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Thanks, Shay. This is unfortunate :( Calling that everywhere throughout the Ruby space will be cumbersome. Is this a problem with the IronRuby interop? Or is it a problem with the WPF databinding system? I suppose there are two ways to make this more automated... create a decorator for all classes that are passed up to the View, or create a converter that the view uses that does this for you. – Brian Genisio Jul 31 '10 at 11:59
Its interesting, actually. Really quickly, I added a ValueConverter that calls `(value as dynamic).to_clr_string();`. It said that it failed to find the method :( I want to avoid calling `to_clr_string` all over my beautiful Ruby code :) – Brian Genisio Jul 31 '10 at 21:46
So, I was just being dumb. I created a value converter called ToStringConverter that simply returns `value != null ? value.ToString() : null;` and I plug it into my XAML. All is good. Thanks, Shay! – Brian Genisio Aug 06 '10 at 14:49
Cool! glad I could help you get to the solution! – Shay Friedman Aug 06 '10 at 17:04

Why do some WPF binding fail against IronRuby properties?

2 Answers2