Walkthrough: Displaying SmartTags
Smart tags are deprecated in favor of light bulbs. See Walkthrough: Displaying Light Bulb Suggestions.
Smart tags are tags on text that expand to display a set of actions. For example, in a Visual Basic or Visual C# project, a red line appears under a word when you rename an identifier such as a variable name. When you move the pointer over the underline, a button is displayed near the pointer. If you click the button, a suggested action is displayed, for example, Rename IsRead to IsReady. If you click the action, all references to IsRead in the project are renamed IsReady.
Although smart tags are part of the IntelliSense implementation in the editor, you can implement smart tags by subclassing SmartTag, and then implementing the ITagger<T> interface and the IViewTaggerProvider interface.
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Other kinds of tags can be implemented in a similar manner. |
The following walkthrough shows how to create a smart tag that appears on the current word and has two suggested actions: Convert to upper case and Convert to lower case.
Prerequisites
To follow this walkthrough, you must install the Visual Studio SDK. For more information, see Visual Studio SDK.
To create a MEF project
Create an Editor Classifier project. Name the solution SmartTagTest.
Open the source.extension.vsixmanifest file in the VSIX Manifest Editor.
Make sure that the Assets section contains a Microsoft.VisualStudio.MefComponent type, the Source is set to A project in current solution, and Project is set to SmartTagTest.dll.
Save and close source.extension.vsixmanifest.
Add the following reference to the project, and set CopyLocal to false:
Microsoft.VisualStudio.Language.Intellisense
Delete the existing class files.
To implement a tagger for smart tags
Add a class file and name it TestSmartTag.
Add a constructor for this class that calls the base constructor with a SmartTagType of Factoid, which will cause a blue line to appear under the first character of a word. (If you use Ephemeral, a red line will appear under the last character of the word.)
Add a class named TestSmartTagger that inherits from ITagger<T> of type TestSmartTag, and implements IDisposable.
Add a constructor that sets the private fields, and subscribes to the LayoutChanged event.
Implement the Dispose method so that it unsubscribes from the LayoutChanged event.
To implement the smart tag tagger provider
Add a class named TestSmartTagTaggerProvider that inherits from IViewTaggerProvider. Export it with a ContentTypeAttribute of "text", a OrderAttribute of Before="default", and a TagTypeAttribute of SmartTag.
Import the ITextStructureNavigatorSelectorService as a property.
Implement the CreateTagger<T> method.
To implement smart tag actions
Create two classes, the first named UpperCaseSmartTagAction and the second named LowerCaseSmartTagAction. Both classes implement ISmartTagAction.
Both classes are alike except that one calls ToUpper and the other calls ToLower. The following steps cover only the uppercase action class, but you must implement both classes. Use the steps for implementing the uppercase action as a pattern for implementing the lowercase action.
Declare a set of private fields.
Add a constructor that sets the fields.
Implement the properties as follows.
Implement the Invoke method by replacing the text in the span with its uppercase equivalent.
To test this code, build the SmartTagTest solution and run it in the experimental instance.
To build and test the SmartTagTest solution
Build the solution.
When you run this project in the debugger, a second instance of Visual Studio is instantiated.
Create a text file and type some text.
A blue line should be displayed under the first letter of the first word of the text.
Move the pointer over the blue line.
A button should be displayed near the pointer.
When you click the button, two suggested actions should be displayed: Convert to upper case and Convert to lower case. If you click the first action, all the text in the current word should be converted to upper case. If you click the second action, all the text should be converted to lower case.