Implementing IQuickDocPresenter

Once a provider has identified an element that it can generate documentation for, it creates an instance of IQuickDocPresenter, which is responsible for generating the documentation. It has the following methods:

public interface IQuickDocPresenter
{
  string GetHtml(PsiLanguageType presentationLanguage);
  [CanBeNull] string GetId();
  [CanBeNull] IQuickDocPresenter Resolve(string id);
  void OpenInEditor();
  void ReadMore();
}

The GetId method returns the ID of the current code element being displayed. This may be an XML Doc Comment ID, a simple ID, or even null. It is intended to be used when displaying the name of the code element, or as diagnostics in the case of failure. For example, if GetHtml returns null, the ID is used in a message of "no documentation available for ".

Resolve will create a new instance of IQuickDocPresenter to allow navigation from one code element to another. For example, a C# QuickDoc window for a method can show parameter and return types as hyperlinks. Clicking these will change the content of the QuickDoc view to that of the new type. Typically, this method is very similar to IQuickDocProvider.Resolve and some of the default providers actually call a Resolve overload on their creating provider. Alternatively, if it's a CLR based language, it can be deferred to an instance of QuickDocTypeMemberProvider, which will treat the passed in code element ID as a CLR XML Doc Comment ID. If the presenter doesn't support navigation, or cannot navigate to the item, it can return null, in which case, it should not add hyperlinks to the HTML.

The OpenInEditor and ReadMore methods are called in response to the "go to" or "read more" hyperlinks added to the default HTML template. When the user clicks the hyperlink, the current presenter's Resolve method is called to find the presenter for the target, and the new presenter's OpenInEditor or ReadMore method is called. OpenInEditor is also called if the user holds down Ctrl when clicking a type definition hyperlink.

ReadMore is expected to open further documentation. It can do this with a simple call to Process.Start, passing in a URL to spawn the system browser, or using the HelpSystem component to display product or MSDN documentation (again extensible by implementing IShowHelp).

The most important method is GetHtml. The string returned from this method is displayed verbatim in a web browser control. If the current code element doesn't have any documentation, or the documentation cannot be created, this method should return null, in which case a fallback message, such as "no documentation available for " is displayed.

ReSharper provides a couple of classes to help build the HTML - XmlDocHtmlUtil and XmlDocHtmlPresenter. Typically, the presenter will generate the HTML by calling XmlDocHtmlPresenter.Run which in turn calls methods on XmlDocHtmlUtil, such as XmlDocHtmlUtil.BuildHtml, although the presenter is free to call XmlDocHtmlUtil directly, or create the HTML itself. It is, however, recommended to use the helper classes).

Last modified: 20 April 2023