How to get current Microsoft.VisualStudio.Package.ExpansionProvider class instance?

[cfognom]

I'm making an extension to automatically insert snippets from the completion list without the need of double tapping tab. I can already intercept when a completion item is committed and inserted into the document with IAsyncCompletionCommitManager.TryCommit() (https://learn.microsoft.com/en-us/dotnet/api/microsoft.visualstudio.language.intellisense.asynccompletion.iasynccompletioncommitmanager?view=visualstudiosdk-2022). There I get the snippet shortcut. Now I'm just missing a way to insert the snippet from its shortcut.

I discovered the ExpansionProvider class (https://learn.microsoft.com/en-us/dotnet/api/microsoft.visualstudio.package.expansionprovider?view=visualstudiosdk-2022) which seem to have the methods I need: FindExpansionByShortcut() and InsertNamedExpansion(). Problem is; I don't know how to get the currently active ExpansionProvider. All examples suggest to inherit it, but then I don't get the current one.

How can I get the currently active ExpansionProvider class? Or alternatively the currently active LanguageService/Source class, and then I can use GetSource() and/or GetExpansionProvider() on that.

I'm new to using the VS SDK so any help is appreciated.

[olegtk]

@cfognom, please check this doc, it shows how to expand a snippet by shortcut: https://learn.microsoft.com/en-us/visualstudio/extensibility/walkthrough-implementing-code-snippets?view=vs-2022&tabs=csharp#implement-snippet-expansion-in-the-snippet-picker-ui

You can also look at how Roslyn does it: https://github.com/dotnet/roslyn/blob/ee6e99b318218d61f4ab7d7a219877fa2aaff4c0/src/VisualStudio/Core/Def/Snippets/AbstractSnippetCommandHandler.cs#L302

Unfortunately it's a very old API... We are working on a new, much simpler Visual Studio code snippets API, but nothing is available yet.

[cfognom]

please check this doc, it shows how to expand a snippet by shortcut: https://learn.microsoft.com/en-us/visualstudio/extensibility/walkthrough-implementing-code-snippets?view=vs-2022&tabs=csharp#implement-snippet-expansion-in-the-snippet-picker-ui

I tried to use InsertExpansion(TextSpan, TextSpan, IVsExpansionClient, Guid, IVsExpansionSession) before, but I need to supply an IVsExpansionClient and an IVsExpansionSession. The docs say I can pass null for the IVsExpansionClient but I get a null reference exception when I do, so I think the docs are wrong. Unfortunately I don't see a way to pass the IVsExpansionClient and IVsExpansionSession to the "currently active handlers" in any way. I would have to supply my own implementations, which I don't want.

You can also look at how Roslyn does it: https://github.com/dotnet/roslyn/blob/ee6e99b318218d61f4ab7d7a219877fa2aaff4c0/src/VisualStudio/Core/Def/Snippets/AbstractSnippetCommandHandler.cs#L302

From my quick glance at how Roslyn does it, It seems to use the same interfaces as previously mentioned.

In conclusion, I can not see a way where I can request from the "currently active snippet handler/manager/client" to insert a snippet. Hopefully the new API will have such a feature.