|
|
|
| Title | Drag items from one position in a list to another displaying textual icons |
|---|
| Keywords | list, drag, drag and drop, text icon |
|---|
| Categories | Controls |
|---|
|
|
|
Use drag and drop. When the user clicks on the list or on a label listing the list items, the list's MouseDown event handler calls subroutine PrepareDragIcon to prepare an appropriate drag icon. It then starts the drag.
|
|
Private Sub List1_MouseDown(Button As Integer, Shift As _
Integer, X As Single, Y As Single)
' Prepare the drag icon.
PrepareDragIcon List1, List1.List(List1.ListIndex)
' Start the drag.
List1.Drag
End Sub
' Set this control's DragIcon property.
Private Sub Label1_MouseDown(Index As Integer, Button As _
Integer, Shift As Integer, X As Single, Y As Single)
' Prepare the drag icon.
PrepareDragIcon Label1(Index), Label1(Index).Caption
' Start the drag.
Label1(Index).Drag
End Sub
|
|
|
Subroutine PrepareDragIcon draws the item's text into a PictureBox. For icons, the picture should be 32 by 32
pixels. It copies the picture into an ImageList control and then uses the ImageList's ListImages collection's ExtractIcon method to get an icon. It sets the dragging control's DragIcon to this.
|
|
' Set this control's DragIcon property.
Private Sub PrepareDragIcon(ByVal ctl As Control, ByVal txt _
As String)
' Write the text into the PictureBox.
picIcon.Font.Name = ctl.Font.Name
picIcon.Font.Size = ctl.Font.Size
picIcon.Font.Bold = ctl.Font.Bold
picIcon.Line (0, 0)-(picIcon.ScaleWidth, _
picIcon.ScaleHeight), picIcon.BackColor, BF
picIcon.CurrentX = (picIcon.ScaleWidth - _
picIcon.TextWidth(txt)) / 2
picIcon.CurrentY = (picIcon.ScaleHeight - _
picIcon.TextHeight(txt)) / 2
picIcon.Print txt
picIcon.Picture = picIcon.Image
imlIcon.ListImages.Clear
imlIcon.ListImages.Add , , picIcon.Picture
ctl.DragIcon = imlIcon.ListImages(1).ExtractIcon
End Sub
|
|
|
If the user drops the item on the list, the List1_DragDrop event handler verifies that the drop source is also the list control (it only lets you drag from the list to the list). It determines where the item should go and moves it there.
|
|
Private Sub List1_DragDrop(Source As Control, X As Single, _
Y As Single)
Dim dropped_value As String
Dim new_position As Integer
If Not (Source Is List1) Then Exit Sub
' Get the item's drop index.
new_position = GetListItemIndex(List1, X, Y)
' Add the item in this position.
If new_position > List1.ListCount Then
' Add at the end.
List1.AddItem List1.List(List1.ListIndex)
Else
' Add at this position.
List1.AddItem List1.List(List1.ListIndex), _
new_position
End If
' Remove the item from its old position.
If List1.ListIndex >= 0 Then List1.RemoveItem _
List1.ListIndex
End Sub
|
|
|
If the user drops the item on a label, the Label1_DragDrop event handler verifies that the drop source is also a label (it only lets you drag from a label to a label). It determines the labels the item is being dragged to and from and switches the values in those labels.
|
|
Private Sub Label1_DragDrop(Index As Integer, Source As _
Control, X As Single, Y As Single)
Dim tmp As String
If Not (TypeOf Source Is Label) Then Exit Sub
tmp = Label1(Index).Caption
Label1(Index).Caption = Source.Caption
Source.Caption = tmp
End Sub
|
| |
|
| |
|
|
