The usual way to create toolwindows in a package is described in my last post HOWTO: Create a toolwindow with a ToolWindowPane class in a Visual Studio package. While with add-ins only a usercontrol was required, with packages you need the usercontrol and a class that inherits from ToolWindowPane. That is, two files. When I first learned this, I found it somewhat overkill. But when I started to migrate my MZ-Tools add-in to a package, which has quite a few toolwindows, I found it totally overkill. Furthermore, requiring to decorate the package with a ProvideToolWindow attribute for each toolwindow defeats the 3rd strategy that I exposed in Strategies migrating from Visual Studio add-ins to packages, in which a core plug-in provides the features (and therefore the usercontrols for toolwindows) and a host adapter provides the communication between the host (Visual Studio) and the core plug-in. The host adapter is not aware of the features implemented by the core plug-in, and therefore it shouldn’t use specific toolwindows classes or attributes. I am aware that the ProvideToolWindow attribute and the class that inherits ToolWindowPane serve a purpose which was not available for toolwindows created by add-ins: to show automatically when VS is launched the toolwindows that were open in the last VS sessions. So, the initialization of the toolwindow must be contained in a class and not in the “click event” of the command that shows the toolwindow. But it happens that add-ins can provide that functionality too with minimal effort: when unloaded the add-in stores which toolwindows were open and when it is loaded again it shows them. Version 7.0 of MZ-Tools, being an add-in, offered this feature since it was released in 2012.

So, I wanted to create toolwindows in my MZ-Tools package like I was doing in my MZ-Tools add-in. While you can use the automation model (EnvDTE) from a package, alas, the EnvDTE80.Windows2. CreateToolWindow2 method is among the few ones that cannot be used from a package because it requires an EnvDTE.AddIn parameter, that a package cannot provide. Fortunately, the the IVsUIShell interface provides a CreateToolWindow method that can be used from packages. In this new article (equivalent to HOWTO: Create a dockable toolwindow from a Visual Studio .NET add-in) I show how to use it:

HOWTO: Create a toolwindow without a ToolWindowPane class in a Visual Studio package
http://www.mztools.com/articles/2015/MZ2015005.aspx