Adapting Legacy Code to the New Editor

Articolo
04/21/2015

The Visual Studio editor has many features that you can access from existing code components. The following instructions show how to adapt a non-MEF component, for example, a VSPackage, to consume editor functionality. The instructions also show how to use adapters to get the services of the editor in both managed and unmanaged code.

Editor Adapters

Editor adapters, or shims, are wrappers for editor objects that also expose the classes and interfaces in the Microsoft.VisualStudio.TextManager.Interop API. You can use the adapters to move between non-editor services for example, Visual Studio shell commands, and editor services. (This is how the editor is currently hosted in Visual Studio.) Adapters also enable legacy editor and language service extensions to work correctly in Visual Studio.

Using Editor Adapters

The IVsEditorAdaptersFactoryService provides methods that switch between the new editor interfaces and the legacy interfaces, and also methods that create adapters.

If you are using this service in a MEF component part, you can import the service as follows.

[Import(typeof(IVsEditorAdaptersFactoryService))]
internal IVsEditorAdaptersFactoryService editorFactory;

If you want to use this service in a non-MEF component, follow the instructions in the "Using Visual Studio Editor Services in a Non-MEF Component" section later in this topic.

Switching Between the New Editor API and the Legacy API

Use the following methods to switch between an editor object and a legacy interface.

Method	Conversion
GetBufferAdapter	Converts an ITextBuffer to an IVsTextBuffer.
GetDataBuffer	Converts an IVsTextBuffer to an ITextBuffer.
GetDocumentBuffer	Converts an IVsTextBuffer to an ITextBuffer.
GetViewAdapter	Converts an ITextView to an IVsTextView.
GetWpfTextView	Converts an IVsTextView to an IWpfTextView.

Creating Adapters

Use the following methods to create adapters for legacy interfaces.

Method	Conversion
CreateVsCodeWindowAdapter	Creates an IVsCodeWindow.
CreateVsTextBufferAdapter	Creates an IVsTextBuffer for a specified IContentType.
CreateVsTextBufferAdapter	Creates an IVsTextBuffer.
CreateVsTextBufferCoordinatorAdapter	Creates an IVsTextBufferCoordinator.
CreateVsTextViewAdapter	Creates an IVsTextView for an ITextViewRoleSet.
CreateVsTextViewAdapter	Creates an IVsTextView.

Creating Adapters in Unmanaged Code

All adapter classes are registered to be local co-creatable, and can be instantiated by using the VsLocalCreateInstance() function.

All adapters are created by using the GUIDs that are defined in the vsshlids.h file in the ..\VisualStudioIntegration\Common\Inc\ folder of the Visual Studio SDK installation. To create an instance of VsTextBufferAdapter, use the following code.

IVsTextBuffer *pBuf = NULL;
VsLocalCreateInstance(CLSID_VsTextBuffer, NULL, CLSCTX_INPROC_SERVER, IID_IVsTextBuffer, (void**)&pBuf);

Creating Adapters in Managed Code

In managed code, you can co-create the adapters in the same way as that described for unmanaged code. You can also use a MEF service that lets you create and interact with adapters. This manner of getting an adapter enables more fine-grained control than you have when you co-create it.

To create an adapter for IVsTextView

Add a reference to Microsoft.VisualStudio.Editor.dll. Make sure that CopyLocal is set to false.

Instantiate the IVsEditorAdaptersFactoryService, as follows.

using Microsoft.VisualStudio.Editor;
...
IVsEditorAdaptersFactoryService adapterFactoryService = ComponentModel.GetService<IVsEditorAdaptersFactoryService>();

Call the CreateX() method.

adapterFactoryService.CreateTextViewAdapter(textView);

Using the Visual Studio Editor Directly from Unmanaged Code

The Microsoft.VisualStudio.Platform.VSEditor namespace and the Microsoft.VisualStudio.Platform.VSEditor.Interop namespace expose COM-callable interfaces as IVx* interfaces. For example, the Microsoft.VisualStudio.Platform.VSEditor.Interop.IVxTextBuffer interface is the COM version of the ITextBuffer interface. From the IVxTextBuffer, you can get access to the buffer snapshots, modify the buffer, listen for text-change events on the buffer, and create tracking points and spans. The following steps show how to access an IVxTextBuffer from a IVsTextBuffer.

To get an IVxTextBuffer

The definitions for the IVx* interfaces are in the VSEditor.h file in the ..\VisualStudioIntegration\Common\Inc\ folder of the Visual Studio SDK installation.

The following code instantiates a text buffer by using the IVsUserData->GetData() method. In the following code, pData is a pointer to an IVsUserData object.

#include <textmgr.h>
#include <VSEditor.h>
#include <vsshlids.h>

CComPtr<IVsTextBuffer> pVsTextBuffer;
CComPtr<IVsUserData> pData;
CComPtr<IVxTextBuffer> pVxBuffer;
...
if (SUCCEEDED(pVsTextBuffer->QueryInterface(IID_IVsUserData, &pData))
{
    CComVariant vt;
    if (SUCCEEDED(pData->GetData(GUID_VxTextBuffer, &vt)) &&
    (vt.Type == VT_UNKNOWN) && (vt.punkVal != NULL))
    {
        vt.punkVal->QueryInterface(IID_IVxTextBuffer, (void**)&pVxBuffer);
    }
}

Using Visual Studio Editor Services in a Non-MEF Component

If you have an existing managed code component that does not use MEF and you want to use the services of the Visual Studio editor, you must add a reference to the assembly that contains the ComponentModelHost VSPackage and get its SComponentModel service.

To consume Visual Studio editor components from a non-MEF component

Add a reference to the Microsoft.VisualStudio.ComponentModelHost.dll assembly in the ..\Common7\IDE\ folder of the Visual Studio installation. Make sure that CopyLocal is set to false.
Add a private IComponentModel member to the class in which you want to use Visual Studio editor services, as follows.
```
using Microsoft.VisualStudio.ComponentModelHost;
....
private IComponentModel componentModel;
```

Instantiate the component model in the initialization method for your component.

componentModel =
 (IComponentModel)Package.GetGlobalService(typeof(SComponentModel));

After this, you can get any one of the Visual Studio editor services by calling the IComponentModel.GetService<T>() method for the service you want.
```
textBufferFactoryService =
     componentModel.GetService<ITextBufferFactoryService>();   
```

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