Bug 3698 - XamlServices throws "duplicate key"
Summary: XamlServices throws "duplicate key"
Status: NEW
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 2.10.x
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2012-02-29 17:58 UTC by Olaf Japp
Modified: 2012-02-29 17:58 UTC (History)
1 user (show)

Is this bug a regression?: ---
Last known good build:

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Description Olaf Japp 2012-02-29 17:58:09 UTC

I am playing with XamlServices and ran into different problems.
I have saved an object to XAML with no problem.
I could also deserialize the XAML.
But when I add two XmlnsDefinition's I get the following exception "An element with the same key already exists in the dictionary"

Here is the reproducible code. 
using System;
using System.Xaml;
using System.IO;
using System.Windows.Markup;

[assembly: XmlnsDefinition("http://www.riams.net/PresentationFramework", "Test")]
[assembly: XmlnsDefinition("http://www.riams.net/PresentationFramework", "Test.Bla")]

namespace Test
	class MainClass
		public static void Main (string[] args)
				Test tst = new Test();
				using (TextWriter writer = File.CreateText("/Users/olaf/test.xaml"))
  					XamlServices.Save(writer, tst);
				Console.WriteLine ("OK");
			catch(Exception ex)
				Console.WriteLine (ex.Message);
	public class Test

I get the same exception when I add the following line of code:
public static readonly DependencyProperty LeftProperty = DependencyProperty.Register("Left", typeof(double), typeof(myUIElement), new PropertyMetadata(0.0));