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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Drawing;
namespace System.Windows.Forms;
/// <summary>
/// This class supports the AllowItemReorder feature.
/// When reordering items ToolStrip and ToolStripItem drag/drop events are routed here.
/// </summary>
internal sealed partial class ToolStripSplitStackDragDropHandler : IDropTarget, ISupportOleDropSource
{
private readonly ToolStrip _owner;
public ToolStripSplitStackDragDropHandler(ToolStrip owner)
{
_owner = owner.OrThrowIfNull();
}
public void OnDragEnter(DragEventArgs e)
{
if (e.Data is not null && e.Data.GetDataPresent(typeof(ToolStripItem)))
{
e.Effect = DragDropEffects.Move;
ShowItemDropPoint(_owner.PointToClient(new Point(e.X, e.Y)));
}
}
public void OnDragLeave(EventArgs e)
{
_owner.ClearInsertionMark();
}
public void OnDragDrop(DragEventArgs e)
{
if (e.Data is not null && e.Data.GetDataPresent(typeof(ToolStripItem)))
{
ToolStripItem item = (ToolStripItem)e.Data.GetData(typeof(ToolStripItem))!;
OnDropItem(item, _owner.PointToClient(new Point(e.X, e.Y)));
}
}
public void OnDragOver(DragEventArgs e)
{
if (e.Data is not null && e.Data.GetDataPresent(typeof(ToolStripItem)))
{
if (ShowItemDropPoint(_owner.PointToClient(new Point(e.X, e.Y))))
{
e.Effect = DragDropEffects.Move;
}
else
{
_owner?.ClearInsertionMark();
e.Effect = DragDropEffects.None;
}
}
}
public void OnGiveFeedback(GiveFeedbackEventArgs e)
{
}
public void OnQueryContinueDrag(QueryContinueDragEventArgs e)
{
}
private void OnDropItem(ToolStripItem droppedItem, Point ownerClientAreaRelativeDropPoint)
{
int toolStripItemIndex = GetItemInsertionIndex(ownerClientAreaRelativeDropPoint);
if (toolStripItemIndex >= 0)
{
ToolStripItem item = _owner.Items[toolStripItemIndex];
if (item == droppedItem)
{
_owner.ClearInsertionMark();
return; // optimization
}
RelativeLocation relativeLocation = ComparePositions(item.Bounds, ownerClientAreaRelativeDropPoint);
droppedItem.Alignment = item.Alignment;
// Protect against negative indicies
int insertIndex = Math.Max(0, toolStripItemIndex);
if (relativeLocation == RelativeLocation.Above)
{
insertIndex = (item.Alignment == ToolStripItemAlignment.Left) ? insertIndex : insertIndex + 1;
}
else if (relativeLocation == RelativeLocation.Below)
{
insertIndex = (item.Alignment == ToolStripItemAlignment.Left) ? insertIndex : insertIndex - 1;
}
else if (((item.Alignment == ToolStripItemAlignment.Left) && (relativeLocation == RelativeLocation.Left)) ||
((item.Alignment == ToolStripItemAlignment.Right) && (relativeLocation == RelativeLocation.Right)))
{
// the item alignment is Tail & dropped to right of the center of the item
// or the item alignment is Head & dropped to the left of the center of the item
// Normally, insert the new item after the item, however in RTL insert before the item
insertIndex = Math.Max(0, (_owner.RightToLeft == RightToLeft.Yes) ? insertIndex + 1 : insertIndex);
}
else
{
// the item alignment is Tail & dropped to left of the center of the item
// or the item alignment is Head & dropped to the right of the center of the item
// Normally, insert the new item before the item, however in RTL insert after the item
insertIndex = Math.Max(0, (_owner.RightToLeft == RightToLeft.No) ? insertIndex + 1 : insertIndex);
}
// If the control is moving from a lower to higher index, you actually want to set it one less than its position.
// This is because it is being removed from its original position, which lowers the index of every control before
// its new drop point by 1.
if (_owner.Items.IndexOf(droppedItem) < insertIndex)
{
insertIndex--;
}
_owner.Items.MoveItem(Math.Max(0, insertIndex), droppedItem);
_owner.ClearInsertionMark();
}
else if (toolStripItemIndex == -1 && _owner.Items.Count == 0)
{
_owner.Items.Add(droppedItem);
_owner.ClearInsertionMark();
}
}
private bool ShowItemDropPoint(Point ownerClientAreaRelativeDropPoint)
{
int i = GetItemInsertionIndex(ownerClientAreaRelativeDropPoint);
if (i >= 0)
{
ToolStripItem item = _owner.Items[i];
RelativeLocation relativeLocation = ComparePositions(item.Bounds, ownerClientAreaRelativeDropPoint);
Rectangle insertionRect = Rectangle.Empty;
switch (relativeLocation)
{
case RelativeLocation.Above:
insertionRect = new Rectangle(_owner.Margin.Left, item.Bounds.Top, _owner.Width - (_owner.Margin.Horizontal) - 1, ToolStrip.s_insertionBeamWidth);
break;
case RelativeLocation.Below:
insertionRect = new Rectangle(_owner.Margin.Left, item.Bounds.Bottom, _owner.Width - (_owner.Margin.Horizontal) - 1, ToolStrip.s_insertionBeamWidth);
break;
case RelativeLocation.Right:
insertionRect = new Rectangle(item.Bounds.Right, _owner.Margin.Top, ToolStrip.s_insertionBeamWidth, _owner.Height - (_owner.Margin.Vertical) - 1);
break;
case RelativeLocation.Left:
insertionRect = new Rectangle(item.Bounds.Left, _owner.Margin.Top, ToolStrip.s_insertionBeamWidth, _owner.Height - (_owner.Margin.Vertical) - 1);
break;
}
_owner.PaintInsertionMark(insertionRect);
return true;
}
else if (_owner.Items.Count == 0)
{
Rectangle insertionRect = _owner.DisplayRectangle;
insertionRect.Width = ToolStrip.s_insertionBeamWidth;
_owner.PaintInsertionMark(insertionRect);
return true;
}
return false;
}
private int GetItemInsertionIndex(Point ownerClientAreaRelativeDropPoint)
{
for (int i = 0; i < _owner.DisplayedItems.Count; i++)
{
Rectangle bounds = _owner.DisplayedItems[i].Bounds;
bounds.Inflate(_owner.DisplayedItems[i].Margin.Size);
if (bounds.Contains(ownerClientAreaRelativeDropPoint))
{
// consider what to do about items not in the display
return _owner.Items.IndexOf(_owner.DisplayedItems[i]);
}
}
if (_owner.DisplayedItems.Count > 0)
{
for (int i = 0; i < _owner.DisplayedItems.Count; i++)
{
if (_owner.DisplayedItems[i].Alignment == ToolStripItemAlignment.Right)
{
if (i > 0)
{
return _owner.Items.IndexOf(_owner.DisplayedItems[i - 1]);
}
return _owner.Items.IndexOf(_owner.DisplayedItems[i]);
}
}
return _owner.Items.IndexOf(_owner.DisplayedItems[_owner.DisplayedItems.Count - 1]);
}
return -1;
}
private RelativeLocation ComparePositions(Rectangle orig, Point check)
{
if (_owner.Orientation == Orientation.Horizontal)
{
int widthUnit = orig.Width / 2;
RelativeLocation relativeLocation = RelativeLocation.Left;
// we can return here if we are checking abovebelowleftright, because
// the left right calculation is more picky than the above/below calculation
// and the above below calculation will just override this one.
if ((orig.Left + widthUnit) >= check.X)
{
relativeLocation = RelativeLocation.Left;
return relativeLocation;
}
else if ((orig.Right - widthUnit) <= check.X)
{
relativeLocation = RelativeLocation.Right;
return relativeLocation;
}
}
if (_owner.Orientation == Orientation.Vertical)
{
int heightUnit = orig.Height / 2;
RelativeLocation relativeLocation = (check.Y <= (orig.Top + heightUnit)) ?
RelativeLocation.Above
: RelativeLocation.Below;
return relativeLocation;
}
Debug.Fail("Could not calculate the relative position for AllowItemReorder");
return RelativeLocation.Left;
}
}
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