How to create an editor with a projection buffer?

Question

I'd like to create an editor to a custom view engine, which hosts C# code around some barriers (let's say <source></source>). In VS2008 this was done by the TextBufferCoordinator, secondary buffers and contained languages. First I tried to convert the project to VS2010 without luck, so I went to see the new Editor APIs. It seems one has to create a IProjectionBuffer, and use spans to link between the codes. But how can you tell the editor to use a ProjectionBuffer? What is the easiest way to convert code that was written using the old ContainedLanguages based API to the new Projection based Editor API?

Answer 1

Hello,

Have you read this ?

http://social.msdn.microsoft.com/Forums/en-US/vseditorprerelease/thread/c5c2ad45-6f61-45c3-8f85-d9ecd26ff548

Chris Granger has replied that easiest thing to use IProjectionBuffer would be to use an IntraText adornment tagger to replace the text with a WPF element.

And the Plateform team will release a sample, so please wait.

Thanks

Chao

Answer 2

This is not a solution. So when example of using the projection text buffer will be available exactly?

I suppose that will be best way to create editors for language-mixins (like ASP.NET Web Pages = HTML+C#/VB).

Answer 3

Even a few hints of how to get started with projection buffers would be useful. The doco at http://msdn.microsoft.com/en-us/library/dd885240.aspx#projection (Inside the Editor) is pretty vague.

We don't need a complete example, just a few snippets and pointers. 

Answer 4

Any updates on this? I can't find a projection buffer sample anywhere.

Answer 5

(I'm interested too ...)

Answer 6

I'd also love a ProjectionBuffer sample or maybe an open source project I could learn off of?

Answer 7

Alright so I'm not sure if anyone will see this, but I figured I'd post a sample since a few people have asked.

First off, you need an instance of IProjectionBufferFactoryService. You can either import this with MEF or use something along the lines of: 

var componentModel = (IComponentModel)Microsoft.VisualStudio.Shell.Package.GetGlobalService(typeof(SComponentModel));

var _ProjectionBufferFactory = componentModel.GetService<IProjectionBufferFactoryService>();

Next you have to create a SnapshotSpan from an ITextSnapShot which can be found on something like an IVsTextBuffer or IVsTextView.

SnapshotSpan subsetSnapshot = new SnapshotSpan(textViewHost.TextView.TextSnapshot, start, length);

Finally, you can create an ElisionBuffer (or ProjectionBuffer similarily) using the ProjectionBufferFactoryService.

var elisBuffer = _ProjectionBufferFactory.CreateElisionBuffer(null, NormalizedSnapshotSpanCollection(subsetSnapshot), ElisionBufferOptions.None);

Hopefully this at least gives someone a starting point as they try to work out projection buffers. I've still struggled to get all the language services working within my projection buffer, but it's a start.

Answer 8

I've also opened a uservoice issue officially requesting this sample here: 

http://visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/6065780-release-a-sample-on-using-projection-buffers-with

Please vote for it, it does not even require registration.