gistfile1.cs

protected override void Initialize()
{ 
    //Other stuff...
    ...
    
    var componentModel = (IComponentModel)this.GetService(typeof(SComponentModel));
    var workspace = componentModel.GetService<Microsoft.VisualStudio.LanguageServices.VisualStudioWorkspace>();
}
 
//Alternatively you can MEF import the workspace. MEF can be tricky if you're not familiar with it
//but here's how you'd import VisuaStudioWorkspace as a property.
 
[Import(typeof(Microsoft.VisualStudio.LanguageServices.VisualStudioWorkspace))]
public VisualStudioWorkspace myWorkspace { get; set; }