How to get active Diagram Name in Add-Ins?

[Slava]

EA.Package aPackage;
aPackage = Repository.GetTreeSelectedPackage();
string PackageName;
string SelectedItemType = Repository.GetTreeSelectedItemType().ToString();
// It fine till this point

string SelectedObjectName =Repository.GetTreeSelectedObject().ToString();
Repository.GetTreeSelectedItem(out myTreeSelectedItem);
// GetTreeSelectedObject and GetTreeSelectedItem do not provide name of selected Item (Diagram)

[«Midnight»]

What about Repository.GetCurrentDiagram(), which should return "a selected diagram" (hopefully the one that's active)?