using System;
using System.Drawing;
using System.Windows.Forms;
using System.Collections.Generic;
namespace WindowsFormsApplication1
{
class DragItem
ListView:
ListView
{
public DragItem
ListView()
{
SetStyle
(ControlStyles.DoubleBuffer | ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint, true
);
UpdateStyles
();
this.MultiSelect = false;
this.
ListViewItemSorter = new
ListViewIndexComparer
();
if
(OSFeature.Feature.IsPresent
(OSFeature.Themes
))
{
this.AllowDrop = true;
this.ItemDrag += new ItemDragEventHandler
(DragItem
ListView_ItemDrag
);
this.DragEnter += new DragEventHandler
(DragItem
ListView_DragEnter
);
this.DragLeave += new EventHandler
(DragItem
ListView_DragLeave
);
this.DragOver += new DragEventHandler
(DragItem
ListView_DragOver
);
this.DragDrop += new DragEventHandler
(DragItem
ListView_DragDrop
);
}
}
void DragItem
ListView_DragDrop
(object sender, DragEventArgs e
)
{
// Retrieve the index of the insertion mark;
int targetIndex = this.InsertionMark.Index;
// If the insertion mark is not visible, exit the method.
if
(targetIndex == -1
)
{
return;
}
// If the insertion mark is to the right of the item with
// the corresponding index, increment the target index.
// Retrieve the dragged item.
ListViewItem draggedItem =
(ListViewItem
)e.Data.GetData
(typeof
(ListViewItem
));
// Insert a copy of the dragged item at the target index.
// A copy must be inserted before the original item is removed
// to preserve item index values.
ListViewItem NewItem =
(ListViewItem
)draggedItem.Clone
();
if
(draggedItem.Index < targetIndex
)
{
if
(targetIndex - draggedItem.Index > 1
)
NewItem.Group = this.Items[targetIndex - 1].Group;
else
NewItem.Group = this.Items[targetIndex].Group;
}
else
{
if
(draggedItem.Index - targetIndex > 1
)
NewItem.Group = this.Items[targetIndex].Group;
else
NewItem.Group = this.Items[targetIndex - 1].Group;
}
if
(this.InsertionMark.AppearsAfterItem
)
{
targetIndex++;
}
this.Items.Insert
(targetIndex, NewItem
);
// Remove the original copy of the dragged item.
this.Items.Remove
(draggedItem
);
}
void DragItem
ListView_DragOver
(object sender, DragEventArgs e
)
{
// Retrieve the client coordinates of the mouse pointer.
Point targetPoint =
this.PointToClient
(new Point
(e.X, e.Y
));
// Retrieve the index of the item closest to the mouse pointer.
//int targetIndex = this.InsertionMark.NearestIndex
(targetPoint
);
int targetIndex = GetNearItem
(targetPoint
).Index;
// Confirm that the mouse pointer is not over the dragged item.
if
(targetIndex > -1
)
{
// Determine whether the mouse pointer is to the left or
// the right of the midpoint of the closest item and set
// the InsertionMark.AppearsAfterItem property accordingly.
Rectangle itemBounds = this.GetItemRect
(targetIndex
);
if
(targetPoint.X > itemBounds.Left +
(itemBounds.Width / 2
))
{
this.InsertionMark.AppearsAfterItem = true;
}
else
{
this.InsertionMark.AppearsAfterItem = false;
}
}
// Set the location of the insertion mark. If the mouse is
// over the dragged item, the targetIndex value is -1 and
// the insertion mark disappears.
this.InsertionMark.Index = targetIndex;
}
void DragItem
ListView_DragLeave
(object sender, EventArgs e
)
{
this.InsertionMark.Index = -1;
}
void DragItem
ListView_ItemDrag
(object sender, ItemDragEventArgs e
)
{
this.DoDragDrop
(e.Item, DragDropEffects.Move
);
}
void DragItem
ListView_DragEnter
(object sender, DragEventArgs e
)
{
e.Effect = e.AllowedEffect;
}
private class
ListViewIndexComparer : System.Collections.IComparer
{
public int Compare
(object x, object y
)
{
return
((ListViewItem
)x
).Index -
((ListViewItem
)y
).Index;
}
}
/// <summary>
/// 搜索最近的
ListViewItem
/// </summary>
/// <param name="ClientPoint">工作区坐标</param>
/// <returns></returns>
public
ListViewItem GetNearItem
(Point ClientPoint
)
{
ListViewItem lvt = this.GetItemAt
(ClientPoint.X, ClientPoint.Y
);
if
(lvt != null
) return lvt;
List<
ListViewItem> vt = new List<
ListViewItem>
();
for
(int i = 1; i < 10; i++
)
{
lvt = this.GetItemAt
(ClientPoint.X, ClientPoint.Y + i
);
if
(lvt != null
) vt.Add
(lvt
);
lvt = this.GetItemAt
(ClientPoint.X, ClientPoint.Y - i
);
if
(lvt != null
) vt.Add
(lvt
);
lvt = this.GetItemAt
(ClientPoint.X + i, ClientPoint.Y
);
if
(lvt != null
) vt.Add
(lvt
);
lvt = this.GetItemAt
(ClientPoint.X + i, ClientPoint.Y + i
);
if
(lvt != null
) vt.Add
(lvt
);
lvt = this.GetItemAt
(ClientPoint.X + i, ClientPoint.Y - i
);
if
(lvt != null
) vt.Add
(lvt
);
lvt = this.GetItemAt
(ClientPoint.X - i, ClientPoint.Y
);
if
(lvt != null
) vt.Add
(lvt
);
lvt = this.GetItemAt
(ClientPoint.X - i, ClientPoint.Y + i
);
if
(lvt != null
) vt.Add
(lvt
);
lvt = this.GetItemAt
(ClientPoint.X - i, ClientPoint.Y - i
);
if
(lvt != null
) vt.Add
(lvt
);
if
(vt.Count > 0
) break;
}
if
(vt.Count == 0
)
{
return null;
}
else if
(vt.Count == 1
)
{
return vt[0];
}
else
{
double HisDis = 0;
int i = 0;
foreach
(ListViewItem item in vt
)
{
double dis = GetDistince
(ClientPoint, item.Position
);
if
(i == 0 || dis < HisDis
)
{
lvt = item;
HisDis = dis;
}
i++;
}
return lvt;
}
}
/// <summary>
/// 两点间的距离
/// </summary>
/// <param name="start">起点</param>
/// <param name="end">终点</param>
/// <returns></returns>
private double GetDistince
(Point start, Point end
)
{
double distince2 = Math.Pow
((start.X - end.X
), 2
) + Math.Pow
((start.Y - end.Y
), 2
);
return Math.Abs
(Math.Sqrt
(distince2
));
}
}
}
本文介绍了一个在XP及更高版本操作系统上实现ListView分组显示的示例代码。通过创建不同的分组并添加到ListView中，展示了如何组织和显示书籍信息，包括标题、作者和年份。
private
void
button1_Click(
object
sender,EventArgse)
...
{
listView1.Groups.Clear();
listView1.Columns.AddRange(newColumnHeader[]...{columnHeader0,columnHeader1,columnHeader2});
"1998"},0,group1);
}
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