My example program is very short. It's comprised only of a Form, a Picturebox, and five subs, most are empty. Here's the code:
Public Class DragAndDropDontWork
Private Sub PictureBox1_DragDrop(ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragDrop
End Sub
Private Sub PictureBox1_DragEnter(ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragEnter
End Sub
Private Sub PictureBox1_DragLeave(ByVal sender As Object, _
ByVal e As System.EventArgs) _
Handles PictureBox1.DragLeave
End Sub
Private Sub PictureBox1_DragOver(ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragOver
If Not (e.Data.GetDataPresent(_
GetType (System.Drawing.Image))) Then
e.Effect = DragDropEffects.None
Me.PictureBox1.Image = Me.PictureBox1.InitialImage
Return
End If
' Set the effect based upon the KeyState.
If ((e.KeyState And (8 + 32)) = (8 + 32) And _
(e.AllowedEffect And DragDropEffects.Link) _
= DragDropEffects.Link) Then
' KeyState 8 + 32 = CTL + ALT
' Link drag-and-drop effect.
e.Effect = DragDropEffects.Link
ElseIf ((e.KeyState And 32) = 32 And _
(e.AllowedEffect And DragDropEffects.Link) _
= DragDropEffects.Link) Then
' ALT KeyState for link.
e.Effect = DragDropEffects.Link
ElseIf ((e.KeyState And 4) = 4 And _
(e.AllowedEffect And DragDropEffects.Move) _
= DragDropEffects.Move) Then
' SHIFT KeyState for move.
e.Effect = DragDropEffects.Move
ElseIf ((e.KeyState And 8) = 8 And _
(e.AllowedEffect And DragDropEffects.Copy) _
= DragDropEffects.Copy) Then
' CTL KeyState for copy.
e.Effect = DragDropEffects.Copy
ElseIf ((e.AllowedEffect And DragDropEffects.Move) _
= DragDropEffects.Move) Then
' By default, the drop action should be move, if allowed.
e.Effect = DragDropEffects.Move
Else
e.Effect = DragDropEffects.None
End If
End Sub
Private Sub DragAndDropDontWork_Load( _
ByVal sender As Object, ByVal e As System.EventArgs) _
Handles Me.Load
Me.AllowDrop = True
End Sub
End Class
If you'll set a break point on each sub and run the app under the debugger, you'll notice that dropping a bitmap into the picturebox doesn't fire any of the events. I hope someone can help me with this, as I have a bad headache and I need to get to work on building a new brick wall. Thanks, BLeRg. | | iamBLeRg Saturday, May 23, 2009 6:57 PM | Wow, that took a while. My day's getting a little long in the tooth, but times not up yet. The solution to my problem is:
Private Sub PictureBox1_DragDrop( _
ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragDrop
' Handle FileDrop data.
If e.Data.GetDataPresent(DataFormats.FileDrop) _
Then
' Assign the file names to a string array, _
' in case the user has selected multiple _
'files.
Dim files As String() = CType( _
e.Data.GetData(DataFormats.FileDrop), String())
Me.fileName = files(0)
Try
' Assign the first image to the _
'picture' variable.
Me.PictureBox1.Image = Image.FromFile( _
files(0))
Catch ex As Exception
MessageBox.Show(ex.Message)
Return
End Try
End If
' Handle Bitmap data.
If e.Data.GetDataPresent(DataFormats.Bitmap) _
Then
Try
' Create an Image and assign it to the _
picture variable.
Me.PictureBox1.Image = CType( _
e.Data.GetData(DataFormats.Bitmap), Image)
Catch ex As Exception
MessageBox.Show(ex.Message)
Return
End Try
End If
' Force the form to be redrawn with the image.
Me.PictureBox1.Invalidate()
End Sub
Private Sub PictureBox1_DragEnter(ByVal sender _
As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragEnter
' Check to be sure that the drag content is _
'the correct type for this
' control. If not, reject the drop.
' If the data is a file or a bitmap, display _
the copy cursor.
If e.Data.GetDataPresent(DataFormats.Bitmap) _
Or e.Data.GetDataPresent( _
DataFormats.FileDrop) Then
e.Effect = DragDropEffects.Copy
Else
e.Effect = DragDropEffects.None
End If
End Sub
Although the keyboard and mouse quit responding a couple of times, forcing me to hold the power button down, I can now consider this matter closed. Thanks, BLeRg. - Marked As Answer byiamBLeRg Sunday, May 24, 2009 6:02 PM
- Edited byiamBLeRg Sunday, May 24, 2009 6:08 PMAdd info to last sentence.
-
| | iamBLeRg Sunday, May 24, 2009 5:59 PM | Well, I found a sample (DragDrop). Sample works why won't my app? I discovered that the picturebox control must have its' allowdrop property set explicetly in code. WaitOnLoad = False. Here's the new code:
Private Sub PictureBox1_DragDrop( _
ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragDrop
' Display the image in the selected PictureBox
'control.
Dim pic As PictureBox = _
CType(sender, PictureBox)
pic.Image = _
CType(e.Data.GetData(DataFormats.Bitmap), Bitmap)
End Sub
Private Sub PictureBox1_DragEnter( _
ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragEnter
' Check to be sure that the drag content is _
'the correct type for this control. If not, _
'reject the drop.
'If (e.Data.GetDataPresent( _
'DataFormats.Bitmap)) Then
' If the Ctrl key was pressed during the drag _
'operation then perform a Move. If not, _
'perform a Copy.
If (e.KeyState And CtrlMask) = CtrlMask Then
e.Effect = DragDropEffects.Move
Else
e.Effect = DragDropEffects.Copy
End If
'Else
'e.Effect = DragDropEffects.None
'End If
End Sub
Private Sub PictureBox1_DragOver( _
ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragOver
' Display the image in the selected _
'PictureBox control.
Dim pic As PictureBox = CType( _
sender, PictureBox)
pic.Image = CType(e.Data.GetData( _
DataFormats.Bitmap), Bitmap)
End Sub
I really need some help with this because I've been at for a couple maybe three hours with not much success. The DragDrop event doesn't fire. The DragEnter event fires, but 'If (e.Data.GetDataPresent(DataFormats.Bitmap)) Then' doesn't recognize when a bitmap is dropped, so I commented it out in order that the inner if block could execute. I'm going to see if I can drag a bitmap out of MyComputer onto the DragDrop sample that I downloaded. I'll also debug it to see what the 'Data' look like. Thanks, BLeRg. | | iamBLeRg Sunday, May 24, 2009 11:31 AM | Nope. Can't drop an image dragged from MyComputer onto the 'Drag and Drop Sample' Pictureboxs. The Pictureboxs in the sample aquire the bitmap image when 'If (e.Data.GetDataPresent(DataFormats.Bitmap)) Then' is executed. So any ideas?
Thanks,
BLeRg. | | iamBLeRg Sunday, May 24, 2009 11:45 AM | Ah. Okay. 'If (e.Data.GetDataPresent(DataFormats.FileDrop)) Then' allows the code in the if block to execute. Not exactly what I want. So now I need to find an app (such as MSPAINT.EXE) which can accept a drag and drop operation from Computer/MyComputer. I'll let you know what I find, but I'm thinking that mc works with files and most other apps (such as mspaint work with images) work with other types, so I'm probably going to have to modify the app so it includes a kind of browser pane to sub for mc.
Thanks,
BLeRg. | | iamBLeRg Sunday, May 24, 2009 1:35 PM | I was (happily) wrong. MSPAINT is a perfect example of what I want to do. So now, how?
Thanks,
BLeRg. | | iamBLeRg Sunday, May 24, 2009 1:41 PM | Wow, that took a while. My day's getting a little long in the tooth, but times not up yet. The solution to my problem is:
Private Sub PictureBox1_DragDrop( _
ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragDrop
' Handle FileDrop data.
If e.Data.GetDataPresent(DataFormats.FileDrop) _
Then
' Assign the file names to a string array, _
' in case the user has selected multiple _
'files.
Dim files As String() = CType( _
e.Data.GetData(DataFormats.FileDrop), String())
Me.fileName = files(0)
Try
' Assign the first image to the _
'picture' variable.
Me.PictureBox1.Image = Image.FromFile( _
files(0))
Catch ex As Exception
MessageBox.Show(ex.Message)
Return
End Try
End If
' Handle Bitmap data.
If e.Data.GetDataPresent(DataFormats.Bitmap) _
Then
Try
' Create an Image and assign it to the _
picture variable.
Me.PictureBox1.Image = CType( _
e.Data.GetData(DataFormats.Bitmap), Image)
Catch ex As Exception
MessageBox.Show(ex.Message)
Return
End Try
End If
' Force the form to be redrawn with the image.
Me.PictureBox1.Invalidate()
End Sub
Private Sub PictureBox1_DragEnter(ByVal sender _
As Object, _
ByVal e As System.Windows.Forms.DragEventArgs) _
Handles PictureBox1.DragEnter
' Check to be sure that the drag content is _
'the correct type for this
' control. If not, reject the drop.
' If the data is a file or a bitmap, display _
the copy cursor.
If e.Data.GetDataPresent(DataFormats.Bitmap) _
Or e.Data.GetDataPresent( _
DataFormats.FileDrop) Then
e.Effect = DragDropEffects.Copy
Else
e.Effect = DragDropEffects.None
End If
End Sub
Although the keyboard and mouse quit responding a couple of times, forcing me to hold the power button down, I can now consider this matter closed. Thanks, BLeRg. - Marked As Answer byiamBLeRg Sunday, May 24, 2009 6:02 PM
- Edited byiamBLeRg Sunday, May 24, 2009 6:08 PMAdd info to last sentence.
-
| | iamBLeRg Sunday, May 24, 2009 5:59 PM |
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