I think that it is not possible to add errors to the list using an add-in in
VS 2005. The collection lacks an Add method. You can submit a suggestion to
add it in the next version:

http://lab.msdn.microsoft.com/ProductFeedback/

Hi Frabrice,

To add items to the error list, you'll need to construct an
ErrorListProvider that implements the IVsTaskProvider interface, as well as
a class that implements IVsErrorItem, as documented in the Visual Studio
SDK for VS 2005. The Managed Package Framework contains some classes that
do all the heavy lifting for you.

In particular the ErrorListProvider and ErrorTask classes in the
Microsoft.VisualStudio.Shell.dll assembly. I have a simple toolwindow
package created with the Visual Studio SDK, that illustrates how to use
these classes to add error items to the Error List dialog. I suspect you
can readily use the same technique from an addin, by referencing the
appropriate MPF assemblies, and retrieving the IServiceProvider interface
from the DTE object.

If you're interested, feel free to drop me an email (just remove that
'.online' from my email address), and I'll zip up and send along the actual
package I wrote that uses these classes. The package in question implements
a toolwindow that you can add errors from, and also handles the ErrorTask's
Navigate event, which reactivates my toolwindow and selects the appropriate
element in a .net listbox that corresponds to the error added to the Error
List.

Sincerely,
Ed Dore [MSFT]

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