Problem with loading component in WPF project

@ds1709 commented on [Wed Aug 14 2019](https://github.com/dotnet/core/issues/3189)

# Issue Title

Problem with loading component in WPF project by calling `Application.LoadComponent(Uri)`.

# General

Version: .NET Core 3.0.0 Preview 8.
OS: Windows 10.
Visual Studio: 2019 16.2.1.
Project Sdk: Microsoft.NET.Sdk.WindowsDesktop.

In the next scenario `Application.LoadComponent(Uri)` throws exception.
Created a simple WPF application with classe `App` and `MainWindow`.
```xml

WinExe
net472
true
1.2.3.54

```
```xml

```
```csharp
public partial class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
var uri = new Uri("/WpfApp1;component/mainwindow.xaml", UriKind.Relative);
var window = LoadComponent(uri); // Exception: Cannot register duplicate Name 'Foo' in this scope.
}
}
```
Key points here are `` in csproj file and named element in MainWindow xaml file. When it's declared, the window code generator creates code like `System.Uri resourceLocater = new System.Uri("/WpfApp1;V1.2.3.54;component/mainwindow.xaml", System.UriKind.Relative);`. As you can see, there's version element in URI. But when `` is not declared, or version is declared in code ([assembly:AssemblyVersion("...")]), then version is missing in generated URI, and exception is not throwing. Same for UserControls.

---

@carlossanlop commented on [Wed Aug 14 2019](https://github.com/dotnet/core/issues/3189#issuecomment-521354854)

> `// Exception: Cannot register duplicate Name 'Foo' in this scope.`

@ds1709 thank you for the details.

@grubioe can you help with this issue? Feel free to transfer it to the dotnet/wpf repo if necessary.

---

@grubioe commented on [Wed Aug 14 2019](https://github.com/dotnet/core/issues/3189#issuecomment-521366474)

@diverdan92 - this might be more related with VS, maybe in the project system, the code generator. Can you route to the right team?