问题
In XAML, a custom namespace can be imported with an xmlns directive:
xmlns:custom="clr-namespace:GreatStuff"
In C#, that namespace can be imported with
using GreatStuff;
Moreover, evaluation of that namespace based on the global (root) namespace can be enforced as follows:
using global::GreatStuff;
How can I enforce evaluation based on the global namespace in XAML?
Background:
I am facing the (admittedly slightly obscure) situation that there is such a namespace global::GreatStuff, which contains a WPF control class named ... GreatStuff (i.e. fully qualified, that's global::GreatStuff.GreatStuff in C#). In the same namespace, I want to use that control in a WPF window.
Interestingly, in this constellation, I cannot use the Name/x:Name attribute on any controls of type global::GreatStuff.GreatStuff in my XAML file for the window:
The type name 'GreatStuff' does not exist in type 'GreatStuff.GreatStuff'. (CS0426)
Note that the very same file compiles fine if I do not specify a Name/x:Name attribute!
Now, why should the compiler assume that by setting a Name/x:Name attribute, I am trying to access something called GreatStuff.GreatStuff.GreatStuff?
The answer can be found by examining the .g.cs file generated from the window XAML file. In that file, the XAML snippet
<custom:GreatStuff x:Name="stuff"/>
gets compiled to the following C# snippet:
internal GreatStuff.GreatStuff stuff;
That is, the fully-qualified name is used, but without the explicit global namespace marker.
Of course, as a field in a class in namespace global::GreatStuff, all of this is wrapped in
namespace GreatStuff {
And so, the poor C# compiler cannot help but assume that stuff is supposed to be of a type global::GreatStuff.GreatStuff.GreatStuff. This could be avoided if in
xmlns:custom="clr-namespace:GreatStuff"
I could enforce that any mentions of that namespace prefix could be converted while enforcing the global namespace.
For reasons external to this question, changing the namespace and/or class names is not an option here.
回答1:
This issue only occurs when all of the following are true:
- You have a class with an identical name as the namespace containing it.
- Within that same namespace, you have a xaml file with an instance of an object that is also declared within that namespace.
- That specific object instance is given a Name or x:Name attribute.
If you cannot modify anything to make any one of those conditions false, then you are working with some very serious restrictions.
As far as I know, this is a limitation of the xaml compiler, and you will need to contact Microsoft about resolving it. The only other thing I can think of would be to try to work around it with a custom build process that builds xaml, allows you to edit the generated files, then builds the code. That would require some research to figure out how to set up.
来源：https://stackoverflow.com/questions/30607193/enforce-global-namespace-in-xaml