Wpf: The x:Key has no intellisense in XAML.

[chenyj796]

• .NET Core Version: 3.1.1
• Windows version: 1909
• Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes
• Is this bug related specifically to tooling in Visual Studio (e.g. XAML Designer, Code editing, etc...)? If yes, please file the issue via the instructions here.
• Security issues and bugs should be reported privately, learn more via our responsible disclosure guidelines.

Problem description:
I have a resource key defined as below:

namespace Wpf1
{
    public abstract class ResourceExtension : TypeExtension
    {
        public ResourceExtension()
        {
            this.Type = this.GetType();
        }
        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            return this.Type;
        }
    }
    public class NormalBackground : ResourceExtension
    {
    }
}

And I use it in XAML as below:

<Window
    x:Class="Wpf1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:Wpf1"
    mc:Ignorable="d"
    Title="MainWindow"
    Height="450"
    Width="800">
    <Window.Resources>
        <SolidColorBrush
            x:Key="{local:NormalBackground}"
            Color="Green" />
    </Window.Resources>
    <Grid>
        <Border
            Background="{StaticResource {local:NormalBackground}}" />
    </Grid>
</Window>

Actual behavior:
When I type the x:Key="{local:NormalBackground}", it has no intellisense, however when I type the Background="{StaticResource {local:NormalBackground}}", the intellisense works fine.

Expected behavior:
The x:Key also has intellisense.

Minimal repro:
Wpf1.zip

[gomathip02]

@chenyj796 - The value of x:key is an arbitrary string and this is an expected behavior.

[weltkante]

@gomathip02 I don't think thats a string, thats a markup extension isn't it? You should be able to expect intellisense for a markup extension.

[miloush]

@gomathip02 that is not even true, x:Key can be any arbitrary object and often it is not a string at all.

A typical example would be using type as a key for a style to apply it to all instances of the type: <Style x:Key="{x:Type TextBlock}">. You should definitely get an autocompletion list of available types in this case and I would think that used to be the case.

[rladuca]

Sorry about that everyone, mistakes were made (don't blame @gomathip02).

Re-opening this. I am not sure if this will end up here in the long run. This seems like a VS issue since (I believe) that we are providing all the necessary information for intellisense to be enabled for x:Key.

Anyway, kicking this to triage again so we can better understand where the issue lies. And thanks for the corrections.

FYI: @SamBent @vatsan-madhavan

[gomathip02]

@chabiss - This seems to be VS issue. Can you pls take a look?