Extension properties

[mrlife]

Sometimes it would be useful to have an extension property, such as adding a property to List that gets/sets an array of the same type.

For example, Blazor <InputSelect> now supports the multiple attribute and binds to an array. I prefer working with lists, so it would be nice if I could continue to use lists but have an asArray property that can be used to get or set the list.

List<int> myList = new();
int[] myArray = { 1, 2, 3, 4, 5, 6 };

myList.asArray = myArray;

[svick]

I don't understand what you're actually asking for. Could you clarify it, ideally by adding an example and explaining why it would be useful?

[mrlife]

Sure, I updated the top post.

[HaloFour]

API suggestions should be posted to the runtime repository.

[DaZombieKiller]

This is effectively a subset of extension everything, which to my knowledge is subsumed by dotnet/csharplang#1711

[huoyaoyuan]

The JS object model is way different from .NET (and most strongly/statically typed systems). It's not able to store arbitrary properties in an object.

[mrlife]

It would would with C# but not the JS interop?

[huoyaoyuan]

If a JS object exposes support for C# dynamic keyword, it would be possible. Otherwise, no.