Description

Currently DPI awareness will be enabled only if a DisableDpiAwarenessAttribute attribute is applied to the entry assembly. Which does not make a lot of sense. This also does not match the behavior of .NET 6.

This PR changes the logic to always enable DPI awareness unless a DisableDpiAwarenessAttribute attribute is applied to the entry assembly.

Customer Impact

WPF applications are not DPI aware. This can be seen by:

dotnet new wpf
dotnet run

And then checking the DPI Awareness column in Task Manager. On .NET 6 the DPI awareness is "System". In .NET 7 preview 1, it is "Unaware".

Regression

This regression was introduced by #5765, which migrated the DPI awareness enablement code from C++ to C#.

Testing

dotnet new wpf

Then replace the contents of MainWindow.xml.cs with:

using System.Windows;
using System.Runtime.InteropServices;

namespace test
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        [DllImport("User32", EntryPoint = "IsProcessDPIAware", CharSet = CharSet.Auto, SetLastError = true)]
        internal static extern bool IsProcessDPIAware();

        public MainWindow()
        {
            InitializeComponent();
            this.Title = IsProcessDPIAware().ToString();
        }
    }
}

Results of running this program on different versions of WPF:

Risk

Low.