/// <summary>
/// make sure the DepObj object has a DepObjInfo object.
/// Store the DepObjInfo object itself as an associated property of the
/// DependencyObject.
/// </summary>
/// <param name="DepObj"></param>
/// <returns></returns>
public static DepObjInfo AssureObjInfo(DependencyObject DepObj)
{
// make sure the DepObjInfo object exists. Store in ObjInfo property.
var objInfo = (DepObjInfo)DepObj.GetValue(ObjInfoProperty);
if (objInfo == null)
{
objInfo = new DepObjInfo()
{
DepObj = DepObj
};
DepObj.SetValue(ObjInfoProperty, objInfo);
}
return(objInfo);
}
/// <summary>
/// Handles changes to the Command property.
/// </summary>
private static void OnCommandChanged(
DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var newCmd = (ICommand)e.NewValue;
var uiElem = d as UIElement;
if (uiElem != null)
{
// make sure the DepObjInfo object exists. Store in ObjInfo property.
var objInfo = DepObjInfo.AssureObjInfo(d);
// hook or unhook the MouseLeave event on this UIElement.
// store the event handler in te DepObjInfo object that stored the DepObj itself.
if (newCmd == null)
{
uiElem.MouseLeave -= objInfo.MouseLeave;
}
else
{
uiElem.MouseLeave += objInfo.MouseLeave;
}
}
}
/// <summary>
/// Sets the Command property.
/// </summary>
public static void SetObjInfo(DependencyObject d, DepObjInfo value)
{
d.SetValue(ObjInfoProperty, value);
}