/// <summary>
/// Raises the DragStart event.
/// </summary>
/// <param name="mousePt">Mouse point at time of event.</param>
/// <param name="offset">Offset compared to target.</param>
/// <param name="c">Control that is source of drag start.</param>
protected virtual void OnDragStart(Point mousePt, Point offset, Control c)
{
// Convert point from client to screen coordinates
mousePt = _target.OwningControl.PointToScreen(mousePt);
DragStartEventCancelArgs ce = new DragStartEventCancelArgs(mousePt, offset, c);
DragStart?.Invoke(this, ce);
// If event is not cancelled then allow dragging
_dragging = !ce.Cancel;
}
private void OnDragStart(object sender, DragStartEventCancelArgs e)
{
_navigator.InternalDragStart(e, _page);
}
private void OnDragStart(object sender, DragStartEventCancelArgs e)
{
Navigator.InternalDragStart(e, null);
}
/// <summary>
/// Raises the DragStart event.
/// </summary>
/// <param name="mousePt">Mouse point at time of event.</param>
/// <param name="offset">Offset of mouse compared to element.</param>
/// <param name="c">Control that starts the drag operation.</param>
protected virtual void OnDragStart(Point mousePt, Point offset, Control c)
{
// Convert point from client to screen coordinates
mousePt = _target.OwningControl.PointToScreen(mousePt);
DragStartEventCancelArgs ce = new DragStartEventCancelArgs(mousePt, offset, c);
if (DragStart != null)
DragStart(this, ce);
// If event is not cancelled then allow dragging
_dragging = !ce.Cancel;
}
internal void InternalDragStart(DragStartEventCancelArgs e, KryptonPage page)
{
if (DesignMode)
e.Cancel = true;
else
{
// Should not already be dragging, but if we are then ensure correct sequence of calls
if (_pageDragging)
{
_pageDragging = false;
if (DragPageNotify != null)
DragPageNotify.PageDragQuit(this);
}
// Create a list of the pages being dragged
if (page != null)
_dragPages = new KryptonPage[] { page };
else
{
// Providing 'null' means we want all the pages
List<KryptonPage> list = new List<KryptonPage>();
foreach (KryptonPage p in Pages)
list.Add(p);
_dragPages = list.ToArray();
}
// Do any of the dragging pages have a flag set saying they can be dragged?
bool allowPageDrag = false;
foreach(KryptonPage p in _dragPages)
if (p.AreFlagsSet(KryptonPageFlags.AllowPageDrag))
{
allowPageDrag = true;
break;
}
// Generate event allowing the DragPageNotify setting to be updated before the
// actual drag processing occurs. You can even cancel the drag entirely.
PageDragCancelEventArgs de = new PageDragCancelEventArgs(e.Point, e.Offset, e.Control, _dragPages);
de.Cancel = (!AllowPageDrag || !allowPageDrag);
OnBeforePageDrag(de);
if (!de.Cancel)
{
// Update with any changes made by the event
List<KryptonPage> list = new List<KryptonPage>();
foreach (KryptonPage p in de.Pages)
list.Add(p);
_dragPages = list.ToArray();
if (DragPageNotify != null)
{
// Give the notify interface a chance to reject the attempt to drag
DragPageNotify.PageDragStart(this, this, de);
_pageDragging = !de.Cancel;
}
}
e.Cancel = de.Cancel;
}
}
