Support equivalent of ComposeExportedValue in System.Composition

[dsplaisted]

System.ComponentModel.Composition (MEF1) has the ability to supply imports to an already-instantiated object, via the ComposeExportedValue<T>(T exportedValue) method. As requested by @ZigMeowNyan and @jabbera in #15362, it would be useful to have this ability in System.Composition (MEF2).

[karelz]

We need formal API proposal

[NEKIT-Boss]

Add methods to ContainerConfiguration class:

public ContainerConfiguration WithInstance<TExport> (TExport instance);
public ContainerConfiguration WithInstance<TExport> (string contractName, TExport instance);
public ContainerConfiguration WithInstance (Type t, object instance);
public ContainerConfiguration WithInstance (Type t, string contractName, object instance);

[siobhanc]

Just adding a +1 to this request. Heavily reliant on ComposeExportedValue and without it, or a sensible workaround, will have to completely redesign my system in order to port to .Net Core

[exones]

This is very frustrating lack of functionality, I join @siobhanc in his comment

[pascalpfeil]

+1 for this

[gthvidsten]

+1 (Surprised nothing has happened after 2.5 years!)

[danmoseley]

Nobody has made a formal API proposal. Guidelines for the format are in the docs folder in this repo. Then the API board can review. If approved, we would welcome a PR with tests from the community.

[gthvidsten]

@danmosemsft Care to provide a direct link to the guideline?

[danmoseley]

Sure...was on phone. Here
https://github.com/dotnet/corefx/blob/master/Documentation/project-docs/api-review-process.md

[ericstj]

I believe this is now tracked with #29400