'Declaration
 
Public Overridable Sub Changed( _
   ByVal subhint As Integer, _
   ByVal oldI As Integer, _
   ByVal oldVal As Object, _
   ByVal oldRect As RectangleF, _
   ByVal newI As Integer, _
   ByVal newVal As Object, _
   ByVal newRect As RectangleF _
) 

public virtual void Changed( 
   int subhint,
   int oldI,
   object oldVal,
   RectangleF oldRect,
   int newI,
   object newVal,
   RectangleF newRect
)

Parameters

subhint

the value for GoChangedEventArgs.SubHint

oldI

An integer value.

oldVal

An Object value.

oldRect

A RectangleF value, also useful for PointF, SizeF, and float values.

newI

An integer value.

newVal

An Object value.

newRect

A RectangleF value, also useful for PointF, SizeF, and float values.

Any override of this method and any methods that this calls should not further modify this object, either directly or indirectly.

Each of your property setters should call this method after actually changing the object's state. You should only call this method if the property's value actually changed. You should use the oldI, oldVal, and/or oldRect parameters for passing the previous old property value. You should use the newI, newVal, and/or newRect parameters for passing the new property value. The old and new values can be used by GoDocument.Changed event handlers to update their state. A special case of such event handlers is the GoUndoManager, which records the old and new values so that it can perform undo and redo operations.

If SuspendsUpdates is true (it is normally false of course), this method does nothing. Your override of this method should check for SuspendsUpdates before invoking any updating functionality. If this object is part of a layer, it calls IGoLayerCollectionContainer.RaiseChanged with a hint of GoLayer.GoLayer.ChangedObject. If there are any observers watching changes to this object, this method calls OnObservedChanged on each of this object's observers.

A number of subhints are pre-defined:

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

GoObject Class
GoObject Members
AddObserver Method
RemoveObserver Method