Answered Problem with DragDrop and double clicking

[jcardana]

There are conflicts between trying to select an item (single-click), double-clicking an item "to open" and dragdrop.
I had the dragdrop working copying one item to another list. But now when I try to doubleclick to "open" an item, I find myself in the drapdrop methods.
As always, I add one thing and I break another.

Thank for any help you have to offer,
Joe

    Sub lstFilenames_DragDrop(sender As Object, e As DragEventArgs) Handles lstFilenames.DragDrop
        If (e.Data.GetDataPresent(DataFormats.StringFormat)) Then
            Dim rcvFilename As String = CStr(e.Data.GetData(DataFormats.StringFormat))
            Call XferFromComp(rcvFilename)
        End If
    End Sub
   
    Sub lstFilenames_DragOver(sender As Object, e As DragEventArgs) Handles lstFilenames.DragOver
        e.Effect = DragDropEffects.Move
    End Sub
   
    Sub lstFilenames_KeyDown(sender As Object, e As KeyEventArgs) Handles lstFilenames.KeyDown
        If e.KeyCode = Keys.Enter Then
            If SelectedPathFilename <> "" Then OpenPresetFile(SelectedPathFilename)
        End If
    End Sub
   
    Sub lstFilenames_MouseDown(sender As Object, e As MouseEventArgs) Handles lstFilenames.MouseDown
        lstFilenames.SelectedIndex = lstFilenames.SelectedIndex
        Application.DoEvents()
        If lstFilenames.Items.Count = 0 Then
            Return
        Else
            Dim selFilename As String = lstFilenames.Items(lstFilenames.SelectedIndex).ToString
            Dim dde As DragDropEffects
            dde = DoDragDrop(selFilename, DragDropEffects.Move)
        End If
        Application.DoEvents()
        Select Case e.Clicks
            Case 2
                If SelectedPathFilename <> "" Then OpenPresetFile(SelectedPathFilename)
                Application.DoEvents()
        End Select
    End Sub

 

[JohnH]

Use MouseDown to store the point, then use MouseMove to calculate a treshold (if MouseButtons.Left) before starting drag-drop . By doing this you allow some slack for drag-drop and it doesn't interfere with click/doubleclick.

Default treshold is 4 pixels, but it could change for system settings and DPI. There is an API for this with SM_CXDRAG setting: GetSystemMetricsForDpi function (winuser.h) - Win32 apps

The number of pixels on either side of a mouse-down point that the mouse pointer can move before a drag operation begins. This allows the user to click and release the mouse button easily without unintentionally starting a drag operation.

 

[jcardana]

Thank you... another road block overcome! I just found the reading list so I'm going to try and learn something!