TreeView DragDrop

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Hi guys!

I feel very funny because this is the first time that i'm asking a question in a forum. I'm gonna try to describe my problem as clear as possible cuz' i'm not that good with english.

I'm trying to program a 'drag and drop' from one treeview to another. I know it's very easy to manage it but i want to make it look like u really drag the node text from the tree view.

This is what i did so far:

I created a windows form with a label and with a transparency key so that only the label will be visible. I have set the form TopMost to True and declared it in the main form where I should do the drag.
On the mousedown event of the treeview from which the name should be dragged, i relocated the moving form to the treenode and gave the text of the treenode.

The code looks like this:

Private Sub treeFrom_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles treeFrom.MouseDown
       
       Dim name As String
       Dim key As String

       If Not treeFrom.GetNodeAt(e.Location) Is Nothing Then
           key = treeFrom.GetNodeAt(e.Location).Tag
           name = treeFrom.Nodes(key).Text
          
                    
           frm.SetTheLabelName(name)
           frm.Location = New Point(Me.Location.X + sender.Location.X + e.Location.X, Me.Location.Y + sender.Location.Y + e.Location.Y)

           blnDrag = True 

       End If

End Sub

The new location of the form is still not perfect but i will manage it so the label text of the form will fit exactly above the treenode text.

This is the mousemove event of the treenode:

VB

Private Sub treeFrom_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles treeFrom.MouseMove

        If e.Button = Windows.Forms.MouseButtons.Left Then
            frm.Location = New Point(Me.Location.X + treeFrom.Location.X + e.Location.X, _
                                     Me.Location.Y + treeFrom.Location.Y + e.Location.Y)
        End If

End Sub

I also managed it to move over the form with the mousemove form event but the problem is that i have to program it for MouseMove event of each control.

Is there any way to manage it only with the form MouseMove event because when i catch the moving form from one event to other the label jump from one location to the other, and i want it to do the transition smoothly. A great way would be jumping directly from the TreeFrom_MouseDown event to the MouseMove event of the moving form but I don't know if that is possilbe somehow.

Posted 4-Feb-10 11:29am

Bujar Tahiri

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2 solutions

Solution 2

Hey Steve, thnx for the solution, I was laughing with it for about half an hour :laugh: . I can't believe I'm an MCAD and never used Capture.

I tried a lot of complicated things not knowing that I could use that, it replaces my 30 lines of code with a single row.

Thnx again :-D , You're my best codeproject buddy so far ;P lol

Posted 5-Feb-10 3:16am

Bujar Tahiri

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Steve Echols · Accepted Answer · 2010-02-04T18:17:00

You need to "capture" the mouse so all mouse move events are sent to your controls handler. Here's a simple example.

C#

private void treeView1_MouseDown(object sender, MouseEventArgs e)
{
    treeView1.Capture = true;
    _dragging = true;
}
private void treeView1_MouseMove(object sender, MouseEventArgs e)
{
    if (_dragging)
    {
        label1.Text = "Tree: " + e.X.ToString() + ", " + e.Y.ToString();
    }
}
private void treeView1_MouseUp(object sender, MouseEventArgs e)
{
    treeView1.Capture = false;
    _dragging = false;
}

Note: X and Y positions will be relative to the control window.

Is that what you're looking for?