added wxTreeCtrl::CollapseAll[Children]() and IsEmpty() methods; documented wxTreeItemId (patch 1622125)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@44116 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/treectrl.h

@@ -172,6 +172,9 @@ public:
     virtual bool IsSelected(const wxTreeItemId& item) const = 0;
         // is item text in bold font?
     virtual bool IsBold(const wxTreeItemId& item) const = 0;
+        // is the control empty?
+    bool IsEmpty() const;
+
 
     // number of children
     // ------------------
@@ -293,6 +296,10 @@ public:
     void ExpandAll();
         // collapse the item without removing its children
     virtual void Collapse(const wxTreeItemId& item) = 0;
+        // collapse the item and all its childs and thats childs
+    void CollapseAllChildren(const wxTreeItemId& item);
+        // collapse all items
+    void CollapseAll();
         // collapse the item and remove all children
     virtual void CollapseAndReset(const wxTreeItemId& item) = 0;
         // toggles the current state