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If you add items to the ListView control on a Microsoft Windows form, you cannot reorder the items by dragging
the items in the ListView control at run time.
To work around this problem, provide drag-and-drop
functionality to the ListView control as follows:
Add the following code to the
ListView1_ItemDrag event handler.
Microsoft Visual Basic .NET or Microsoft Visual Basic 2005 code
'Begins a drag-and-drop operation in the ListView control.
ListView1.DoDragDrop(ListView1.SelectedItems, DragDropEffects.Move)
Microsoft Visual C# .NET or Microsoft Visual C# 2005 code
//Begins a drag-and-drop operation in the ListView control.
listView1.DoDragDrop(listView1.SelectedItems, DragDropEffects.Move);
Add the following code to the
ListView1_DragEnter event handler.
Visual Basic .NET or Visual Basic 2005 code
Dim i As Integer
For i = 0 To e.Data.GetFormats().Length - 1
If e.Data.GetFormats()(i).Equals("System.Windows.Forms.ListView+SelectedListViewItemCollection") Then
'The data from the drag source is moved to the target.
e.Effect = DragDropEffects.Move
End If
Next
Visual C# .NET or Visual C# 2005 code
int len=e.Data.GetFormats().Length-1 ;
int i;
for (i = 0 ; i<=len ;i++)
{
if (e.Data.GetFormats()[i].Equals("System.Windows.Forms.ListView+SelectedListViewItemCollection"))
{
//The data from the drag source is moved to the target.
e.Effect = DragDropEffects.Move;
}
}
Add the following code to the
ListView1_DragDrop event handler.
Visual Basic .NET or Visual Basic 2005 code
'Return if the items are not selected in the ListView control.
If ListView1.SelectedItems.Count = 0 Then Return
'Returns the location of the mouse pointer in the ListView control.
Dim p As Point = ListView1.PointToClient(New Point(e.X, e.Y))
'Obtain the item that is located at the specified location of the mouse pointer.
Dim dragToItem As ListViewItem = ListView1.GetItemAt(p.X, p.Y)
If dragToItem Is Nothing Then Return
'Obtain the index of the item at the mouse pointer.
Dim dragIndex As Integer = dragToItem.Index
Dim i As Integer
Dim sel(ListView1.SelectedItems.Count) As ListViewItem
For i = 0 To ListView1.SelectedItems.Count - 1
sel(i) = ListView1.SelectedItems.Item(i)
Next
For i = 0 To ListView1.SelectedItems.Count - 1
'Obtain the ListViewItem to be dragged to the target location.
Dim dragItem As ListViewItem = sel(i)
Dim itemIndex As Integer = dragIndex
If itemIndex = dragItem.Index Then Return
If dragItem.Index < itemIndex Then
itemIndex = itemIndex + 1
Else
itemIndex = dragIndex + i
End If
'Insert the item in the specified location.
Dim insertitem As ListViewItem = dragItem.Clone
ListView1.Items.Insert(itemIndex, insertitem)
'Removes the item from the initial location while
'the item is moved to the new location.
ListView1.Items.Remove(dragItem)
Next
Visual C# .NET or Visual C# 2005 code
//Return if the items are not selected in the ListView control.
if(listView1.SelectedItems.Count==0)
{
return;
}
//Returns the location of the mouse pointer in the ListView control.
Point cp = listView1.PointToClient(new Point(e.X, e.Y));
//Obtain the item that is located at the specified location of the mouse pointer.
ListViewItem dragToItem = listView1.GetItemAt(cp.X, cp.Y);
if(dragToItem==null)
{
return;
}
//Obtain the index of the item at the mouse pointer.
int dragIndex = dragToItem.Index;
ListViewItem[] sel=new ListViewItem [listView1.SelectedItems.Count];
for(int i=0; i<=listView1.SelectedItems.Count-1;i++)
{
sel[i]=listView1.SelectedItems[i];
}
for(int i=0; i<sel.GetLength(0);i++)
{
//Obtain the ListViewItem to be dragged to the target location.
ListViewItem dragItem = sel[i];
int itemIndex = dragIndex;
if(itemIndex==dragItem.Index)
{
return;
}
if(dragItem.Index<itemIndex)
itemIndex++;
else
itemIndex=dragIndex+i;
//Insert the item at the mouse pointer.
ListViewItem insertItem = (ListViewItem)dragItem.Clone();
listView1.Items.Insert(itemIndex, insertItem);
//Removes the item from the initial location while
//the item is moved to the new location.
listView1.Items.Remove(dragItem);
}
Start Microsoft Visual Studio .NET or Microsoft Visual Studio 2005.
Create a new Windows application by using Visual Basic
.NET, Visual Basic 2005, Visual C# 2005, or Visual C# .NET.
By default, Form1 is created.
Add the ListView control to
Form1.
Right-click ListView1, and then click
Properties.
In the Properties dialog box, click the
Items property, and then click the ellipsis
button (...).
In the ListViewItem Collection Editor
dialog box, click Add four times.
Set the Text property of
the first ListViewItem control to Item1, set the
Text property of the second ListViewItem control to
Item2, set the Text property of the third
ListViewItem control to Item3, and then set the
Text property of the fourth ListViewItem control to
Item4.
In the ListViewItem Collection Editor
dialog box, click OK.
In the Properties dialog box of
ListView1, set the View property to
List.
Set the AllowDrop property of
ListView1 to True.
On the Build menu, click Build
Solution.
On the Debug menu, click
Start.
Try to drag Item1 to
a new location in the ListView control.
For additional information, click the following article number
to view the article in the Microsoft Knowledge Base:
822482
(http://support.microsoft.com/kb/822482/
)
HOW TO: Provide Drag-and-Drop Functionality in Microsoft Windows Applications by Using Microsoft Visual Basic .NET