Walkthrough: Link a content type to a file name extension

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You can define your own content type and link a file name extension to it by using the editor Managed Extensibility Framework (MEF) extensions. In some cases, the file name extension is already defined by a language service. But, to use it with MEF, you must still link it to a content type.

Create a MEF project

  1. Create a C# VSIX project. (In the New Project dialog, select Visual C# / Extensibility, then VSIX Project.) Name the solution ContentTypeTest.

  2. In the source.extension.vsixmanifest file, go to the Assets tab, and set the Type field to Microsoft.VisualStudio.MefComponent, the Source field to A project in current solution, and the Project field to the name of the project.

Define the content type

  1. Add a class file and name it FileAndContentTypes.

  2. Add references to the following assemblies:

    1. System.ComponentModel.Composition

    2. Microsoft.VisualStudio.Text.Logic

    3. Microsoft.VisualStudio.CoreUtility

  3. Add the following using directives.

    using System.ComponentModel.Composition;
using Microsoft.VisualStudio.Text.Classification;
using Microsoft.VisualStudio.Utilities;

  4. Declare a static class that contains the definitions.

    internal static class FileAndContentTypeDefinitions
{. . .}

  5. In this class, export a ContentTypeDefinition named "hid" and declare its base definition to be "text".

    internal static class FileAndContentTypeDefinitions
{
    [Export]
    [Name("hid")]
    [BaseDefinition("text")]
    internal static ContentTypeDefinition hidingContentTypeDefinition;
}

Link a file name extension to a content type

  • To map this content type to a file name extension, export a FileExtensionToContentTypeDefinition that has the extension .hid and the content type "hid".

    internal static class FileAndContentTypeDefinitions
{
     [Export]
     [Name("hid")]
     [BaseDefinition("text")]
    internal static ContentTypeDefinition hidingContentTypeDefinition;

     [Export]
     [FileExtension(".hid")]
     [ContentType("hid")]
    internal static FileExtensionToContentTypeDefinition hiddenFileExtensionDefinition;
}

Add the content type to an editor export

  1. Create an editor extension. For example, you can use the margin glyph extension described in Walkthrough: Create a margin glyph.

  2. Add the class you defined in this procedure.

  3. When you export the extension class, add a ContentTypeAttribute of type "hid" to it.

    [Export]
[ContentType("hid")]

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