Create Drop Down Helper(IVsTextView)
Instantiates a TypeAndMemberDropdownBars class.
public virtual Microsoft.VisualStudio.Package.TypeAndMemberDropdownBars CreateDropDownHelper (Microsoft.VisualStudio.TextManager.Interop.IVsTextView forView);
If successful, returns a TypeAndMemberDropdownBars object; otherwise, returns a null value.
Every text view can have a pair of combo boxes (implemented in what is called a Navigation bar) that show types and members based on the current location of the caret (the edit cursor). These combo-boxes are also used for quick navigation: selecting an item from the list jumps to that item in the source code. If your language service supports this functionality, you must derive a class from TypeAndMemberDropdownBars and return an instantiation of your class from this method.
The base method always returns a null value, indicating that the Navigation bar should not be used.