Use patterns in more places.

src/VisualStudio/Core/Def/Implementation/NavigationBar/NavigationBarClient.cs

@@ -291,9 +291,8 @@ int IVsDropdownBarClient3.GetEntryImage(int iCombo, int iIndex, out int piImageI
             // represents.  That way the icon will always look right no matter which type of project
             // it is.  For example, if phone/Windows projects have different icons, then this can 
             // ensure we get the right icon, and not just a hardcoded C#/VB icon.
-            if (item is NavigationBarProjectItem)
+            if (item is NavigationBarProjectItem projectItem)
             {
-                var projectItem = (NavigationBarProjectItem)item;
                 if (_workspace.TryGetImageListAndIndex(_imageService, projectItem.DocumentId.ProjectId, out phImageList, out piImageIndex))
                 {
                     return VSConstants.S_OK;

src/VisualStudio/Core/Def/Implementation/Preview/FileChange.cs

@@ -219,9 +219,9 @@ internal override void GetDisplayData(VSTREEDISPLAYDATA[] pData)
             // If these are documents from a VS workspace, then attempt to get the right display
             // data from the underlying VSHierarchy and itemids for the document.
             var workspace = document.Project.Solution.Workspace;
-            if (workspace is VisualStudioWorkspaceImpl)
+            if (workspace is VisualStudioWorkspaceImpl vsWorkspace)
             {
-                if (((VisualStudioWorkspaceImpl)workspace).TryGetImageListAndIndex(_imageService, document.Id, out pData[0].hImageList, out pData[0].Image))
+                if (vsWorkspace.TryGetImageListAndIndex(_imageService, document.Id, out pData[0].hImageList, out pData[0].Image))
                 {
                     pData[0].SelectedImage = pData[0].Image;
                     return;