Feature request: Fully support nullable reference types in the WPF API surface area for .NET 5

[Austin-Lamb]

Mads Torgerson has laid out a call to action for .NET libraries to properly support the C# 8 Nullable Reference Types feature by the time .NET 5 comes out (see here : https://devblogs.microsoft.com/dotnet/embracing-nullable-reference-types/ )

It would be great if WPF can support this feature. Currently, as an example, IValueConverter does not support this correctly - the return type from "Convert" is object but it should be "object?" since it's valid to return a null.

Currently in my WPF app I have to disable nullable reference types on my IValueConverter source files, which is unfortunate for .NET 5 alignment.

Note: there may be more parts of the WPF API surface that should be nullable-ready, IValueConverter is a concrete example I can point to, but this feature request is really to correctly support NRTs for the entire API surface per Mads' post.

[Rand-Random]

Any updates on this issue? Is .NET 7 a possibility?

[lindexi]

See #3062

[pchaurasia14]

Closing this issue in favor of #7563