WPF XAML merge default namespace definitions

Question

In a WPF application, you can create XmlnsDefinitions to map multiple namespaces from another assembly into one reference .

You can take advantage of that to map your own namespaces to the Microsoft default XmlnsDefinition, for example:

[assembly: XmlnsDefinition("http://schemas.microsoft.com/winfx/2006/xaml/presentation", "MyLibrary.MyControls")]

This way, you don't even need to add a reference to your namespace in the XAML file, because they are already mapped to the default "xmlns".

So, if I had a control called "MyControl", I can use it like this (without any namespaces or prefixes):

<MyControl />

My question is : Can I merge the default Microsoft namespaces into a single one?

For example: I want to get rid of the "xmlns:x" namespace by merging it into "xmlns". I would have to reference all the namespaces in " http://schemas.microsoft.com/winfx/2006/xaml " to " http://schemas.microsoft.com/winfx/2006/xaml/presentation ".

Like this:

[assembly: XmlnsDefinition("http://schemas.microsoft.com/winfx/2006/xaml/presentation", "System...")]
[assembly: XmlnsDefinition("http://schemas.microsoft.com/winfx/2006/xaml/presentation", "System...")]
...

So I can turn this:

<Window x:Class="MyProject.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    >

Into this:

<Window Class="MyProject.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    >

Answer 1

You can't override existing namespace mappings as they are already present in the standard assembies, but you can try merging all .NET namespaces into your own XML namespace. Like this:

[assembly: XmlnsDefinition("urn:foobar", "System.Windows.Controls")]
[assembly: XmlnsDefinition("urn:foobar", "System.Windows.Documents")]
[assembly: XmlnsDefinition("urn:foobar", "System.Windows.Shapes")]
// ...
[assembly: XmlnsDefinition("urn:foobar", "FoobarLibrary.Controls")]
// ...

It may work (I haven't tried). Your XAML will look like this:

<Window x:Class="FoobarProject.MainWindow"
    xmlns="urn:foobar"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

Note that you can't get rid of x namespace:

1. It isn't mapped to .NET namespace, it's pure XML namespace and part of XAML language.

2. Doing so would cause conflicts ( x:Name vs. Name ).

Speaking of conflicts, merging namespaces like this is asking for trouble. You are likely to run into name conflicts which these namespaces are designed to solve.