如何从XAML中的CLR命名空间映射类型而不是声明它的汇编？(How do I map a type from a CLR namespace in XAML from an assembly other than the one where it's declared?)

 在XAML中，我想使用来自两个不同程序集的类型，每个程序集都有自己的命名空间。 我不想在xmlns:<xml-namespace>="<clr-namespace>"属性中显式声明名称空间，而是使用[XmlnsDefinition]程序集属性将URI映射到这些类型的名称空间。 
 
 其中一个程序集本身与WPF无关，所以我想避免它引用与WPF相关的程序集，特别是System.Xaml.dll程序集，如果该程序集使用[XmlnsDefinition]属性。 
 
 我有一个像这样组织的Visual Studio解决方案： 
 
Gu.Units.sln
    Gu.Units.csproj // no ref to System.Xaml here
    Gu.Units.Wpf.csproj // references Gu.Units and System.Xaml
 
 在Gu.Units.Wpf.csproj我有这个映射： 
 
[assembly: XmlnsDefinition("http://Gu.com/Units", clrNamespace: "Gu.Units", AssemblyName = "Gu.Units")]
[assembly: XmlnsDefinition("http://Gu.com/Units", clrNamespace: "Gu.Units.Wpf", AssemblyName = "Gu.Units.Wpf")]
[assembly: XmlnsPrefix("http://Gu.com/Units", "units")]
 
 我试图在XAML中使用它，如下所示： 
 
<UserControl x:Class="Gu.Units.Wpf.Demo.Sample"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:units="http://Gu.com/Units">
    <Label Content="{x:Static units:LengthUnit.Millimetres}" />
</UserControl>
 
 但由于某种原因，名称空间Gu.Units似乎被忽略了。 也就是说，它不包含在URI http://Gu.com/Units标识的XML命名空间中。 相反，我得到： 
 
 
 
 名称“LengthUnit”在命名空间“ http://Gu.com/Units ”中不存在。 
 
 
 XAML中的显式名称空间声明 - 即具有xmlns:units="clr-namespace:Gu.Units;assembly=Gu.Units" - 工作正常，但我也想避免这种情况。 
 
 有没有办法，我可以让我的Gu.Units.Wpf.dll程序集提供必要的[XmlnsDefinition]属性来映射Gu.Units.Wpf.dll程序[XmlnsDefinition]的命名空间，以便后者本身不需要对System.Xaml.dll的引用System.Xaml.dll ， System.Xaml.dll没有任何特定于XAML的代码？ 

In XAML, I would like to use types from two different assemblies, each with their own namespace. Rather than declaring the namespaces explicitly in an xmlns:<xml-namespace>="<clr-namespace>" attribute, I would like to use the [XmlnsDefinition] assembly attribute to map a URI to the namespaces for those types.
 
One of the assemblies is not relevant to WPF per se, so I would like to avoid it having any reference to WPF-related assemblies, and in particular the System.Xaml.dll assembly which would be required if that assembly used the [XmlnsDefinition] attribute.
 
I have a Visual Studio Solution that is organized like this:
 
Gu.Units.sln
    Gu.Units.csproj // no ref to System.Xaml here
    Gu.Units.Wpf.csproj // references Gu.Units and System.Xaml
 
In Gu.Units.Wpf.csproj I have this mapping:
 
[assembly: XmlnsDefinition("http://Gu.com/Units", clrNamespace: "Gu.Units", AssemblyName = "Gu.Units")]
[assembly: XmlnsDefinition("http://Gu.com/Units", clrNamespace: "Gu.Units.Wpf", AssemblyName = "Gu.Units.Wpf")]
[assembly: XmlnsPrefix("http://Gu.com/Units", "units")]
 
I have tried to use it in XAML like this:
 
<UserControl x:Class="Gu.Units.Wpf.Demo.Sample"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:units="http://Gu.com/Units">
    <Label Content="{x:Static units:LengthUnit.Millimetres}" />
</UserControl>
 
But for some reason, the namespace Gu.Units seems to be ignored. That is, it is not included in the XML namespace identified by the URI http://Gu.com/Units. Instead, I get:
 
 
 
The name "LengthUnit" does not exist in the namespace "http://Gu.com/Units".
 
 
An explicit namespace declaration in the XAML — i.e. having xmlns:units="clr-namespace:Gu.Units;assembly=Gu.Units" — works fine but I would also like to avoid that.
 
Is there a way that I can have my Gu.Units.Wpf.dll assembly provide the necessary [XmlnsDefinition] attribute to map the namespace from the Gu.Units.dll assembly, so that the latter does not itself need a reference to System.Xaml.dll, nor have any XAML-specific code in it at all?

原文：https://stackoverflow.com/questions/33862121