Need winform example: Drag from Grid to Treeview

[Richard Thurgood]

I'd sure appreciate some help. I see some examples for web applications but I need a simple way to drag/drop a selected row from a grid into a treeview on a winform.

I don't see any properties on the grid that allow drag and I have the lastest evaluation version installed.

Anyone? 

[Jordan]

Hi Richard Thurgood,

We are working on a drag and drop framework for RadControls for WinForms which will allow easy implementation of drag and drop functionality. Unfortunately I cannot give you a specific time frame at the moment, but I think we could estimate that we'll have it for Q3 2008.

In the meantime you can use the drag and drop functionality that is available in Windows Forms to implement dragging from a RadGridView to a RadTreeView control like that:

protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            this.radGridView1.Rows.Add("Name1", "Value1");
            this.radGridView1.Rows.Add("Name2", "Value2");
            this.radGridView1.Rows.Add("Name3", "Value3");

            this.radTreeView1.AllowDrop = true;
            this.radGridView1.MouseDown += new MouseEventHandler(radGridView1_MouseDown);
            this.radTreeView1.DragEnter += new DragEventHandler(radTreeView1_DragEnter);
            this.radTreeView1.DragDrop += new DragEventHandler(radTreeView1_DragDrop);
        }

        void radGridView1_MouseDown(object sender, MouseEventArgs e)
        {
            GridViewRowInfo currentRow = this.radGridView1.MasterGridViewInfo.CurrentRow;
            radGridView1.DoDragDrop(currentRow.Cells[0].Value, DragDropEffects.Copy);
        }

        void radTreeView1_DragDrop(object sender, DragEventArgs e)
        {
            string text = e.Data.GetData(DataFormats.Text).ToString();
            RadTreeNode newNode = new RadTreeNode(text);

            Point p = this.radTreeView1.PointToClient(new Point(e.X, e.Y));
            RadTreeNode targetNode = this.radTreeView1.GetNodeAt(p.X, p.Y);

            RadTreeNodeCollection targetCollection = (targetNode != null) ? targetNode.Nodes : this.radTreeView1.Nodes;
            targetCollection.Add(newNode);
        }

        void radTreeView1_DragEnter(object sender, DragEventArgs e)
        {
            e.Effect = (e.Data.GetDataPresent(DataFormats.Text)) ? DragDropEffects.Copy : DragDropEffects.None;
        }

Hope this helps.

All the best,
Jordan
the Telerik team

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[Richard Thurgood]

That's fantastic!  THANKS!

(NOTE: I had to add columns to the code prior to adding the data, but the sample code was just what I needed)

[Richard Thurgood]

Uh oh - I thought this was going to work but now I see that I have issues with selecting rows, sorting and scrolling since the event is hooked to "MouseDown".  Any other suggestions? 

[Jordan]

Hi Richard,

I tested the project again and indeed found a bug that present when you try to scroll or sort.
The solution is to merely check if the current row is not null :

void radGridView1_MouseDown(object sender, MouseEventArgs e)
        {
            GridViewRowInfo currentRow = this.radGridView1.MasterGridViewInfo.CurrentRow;
            if (currentRow != null)
            {
                radGridView1.DoDragDrop(currentRow.Cells[0].Value, DragDropEffects.Copy);
            }
        }

If that is not what you need, please write back with some more details about the problems that you are experiencing.

Kind regards,
Jordan
the Telerik team

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[Richard Thurgood]

Actually, I already did that. I found that issue shortly after I tried the sample code so I rectified it prior to my post.  That said, you still can't sort, select or scroll properly once you've tied into the mouse down event. 

For example, select a row and then try to sort or scroll. You'll see it doesn't function properly.

Suggestions?

[Jordan]

Hello Richard Thurgood,

It turned out that in order to have the problems solved, you must call  DoDragDrop in the mouse move handler. Here is the solution that I suggest:

private Point startPoint = Point.Empty;
       private GridViewRowInfo currentRow = null;

        void radGridView1_MouseDown(object sender, MouseEventArgs e)
        {
            if (this.radGridView1.GridElement.VScrollBar.ControlBoundingRectangle.Contains(e.Location))
            {
                return;
            }
            if (e.Button != MouseButtons.Left)
            {
                return;
            }
            this.currentRow = this.radGridView1.MasterGridViewInfo.CurrentRow;
            if (this.currentRow == null)
            {
                return;
            }

            this.startPoint = e.Location;
        }

        void radGridView1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button != MouseButtons.Left)
            {
                return;
            }

            if (this.radGridView1.GridElement.VScrollBar.ControlBoundingRectangle.Contains(e.Location))
            {
                return;
            }

            if (Math.Abs(e.X - this.startPoint.X) < SystemInformation.DragSize.Width
              && Math.Abs(e.Y - this.startPoint.Y) < SystemInformation.DragSize.Height)
            {
                return;
            }

            if (this.currentRow == null)
            {
                return;
            }

            radGridView1.DoDragDrop(this.currentRow.Cells[0].Value, DragDropEffects.Copy);
        }

Please give it a try and write me back if you need more assistance.

Sincerely yours,
Jordan
the Telerik team

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[Richard Thurgood]

Thanks for your reply. Yes, this worked. I added:

if (this.radGridView1.GridElement.HScrollBar.ControlBoundingRectangle.Contains(e.Location))
{
 return;
}


...to handle the horizontal scrolling like you did with the vertial scrolling. Well, it works for now and I'll update the code when you have the DragDrop released in Q3.

Thanks again!

[Jordan]

Hi Richard,

Glad to see that I could help.
Just to clarify, we are still evaluating the Drag and Drop framework and I cannot promise you that it will be available in the Q3 2008 release.

Kind regards,
Jordan
the Telerik team

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[Ilya]

Hi there...

I've got all this working from a GridView to nodes in a tree.
On mouse over each of the nodes while dragging from the grid, i really need for each node to highlight. At the moment there is not good visual feedback to show that the item from the grid will be dropping into a specific node.

Can you shed some light on this?

Thanks,
ilya.

[Jordan]

Hi Ilya,

The drop indication that you may have seen in the examples is a part of the RadTreeView drag and drop functionality. Unfortunately, it is not available for usage outside the treeview.
 
A solution I can suggest is to try changing the the cursor when the mouse is over a node in order to give visual feedback.

 
Sincerely yours,
Jordan
the Telerik team

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[Jure]

Hi.

Excellent code, thanks.

Here's the code to highlight a node that is being dragged over (VB.net - use converter for C#):

'class level
Private currentNode As RadTreeNode

Private Sub tree_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles tree.DragOver
        Dim p As Point = Me.tree.PointToClient(New Point(e.X, e.Y))

        If Not currentNode Is Nothing Then
            currentNode.BackColor = Color.Transparent
        End If

        currentNode = Me.tree.GetNodeAt(p.X, p.Y)
        currentNode.BackColor = Color.OrangeRed

    End Sub

Edit: Here's the relevant (though not too clean) code for efficient (only data rows and not header or scrollbar) dragging:

 Private Sub gridView1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles gridView1.MouseDown
        If Me.gridView1.GridElement.VScrollBar.ControlBoundingRectangle.Contains(e.Location) Then
            Return
        End If

        If (Not e.Button = Windows.Forms.MouseButtons.Left) Then
            Return
        End If

        'must be GridDataCellElement and NOT GridHeaderCellElement to drag & drop
        If TypeOf Me.gridView1.ElementTree.GetElementAtPoint(e.Location) Is GridDataCellElement And _
           (Not TypeOf Me.gridView1.ElementTree.GetElementAtPoint(e.Location) Is GridHeaderCellElement) Then
            Me.currentRow = Me.gridView1.MasterGridViewInfo.CurrentRow
        Else
            Me.currentRow = Nothing
        End If

        If Me.currentRow Is Nothing Then
            Return
        End If
        Me.startPoint = e.Location

    End Sub

    Private Sub gridView1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles gridView1.MouseMove
        If Not e.Button = Windows.Forms.MouseButtons.Left Then
            Return
        End If
        If Me.gridView1.GridElement.VScrollBar.ControlBoundingRectangle.Contains(e.Location) Then
            Return
        End If
        If (Math.Abs(e.X - Me.startPoint.X) < SystemInformation.DragSize.Width) And (Math.Abs(e.Y - Me.startPoint.Y) < SystemInformation.DragSize.Height) Then
            Return
        End If
        If Me.currentRow Is Nothing Then
            Return
        End If

        'must be GridDataCellElement to drag & drop
        If TypeOf Me.gridView1.ElementTree.GetElementAtPoint(e.Location) Is GridDataCellElement Then
            Me.gridView1.DoDragDrop(Me.currentRow.Cells(0).Value, DragDropEffects.Copy)
        End If

    End Sub

[Jay]

Has the framework been extended thus far to allow this to work without the windows events?

I'm trying to drag from a treeview to the gridview and none of the gridview events are firing...

please let me know

thanks!

[Victor]

Hello Jure,

Please elaborate on what do you mean by none of the gridview events are firing. I tested drag and drop between RadTreeView and RadGridView and it works correctly. Here is the code that I am testing, feel free to use it as needed:

private void radGridView1_DragEnter(object sender, DragEventArgs e)
{
    if (e.Data.GetDataPresent(typeof(string)))
    {
        e.Effect = DragDropEffects.Copy;
    }
    else
    {
        e.Effect = DragDropEffects.None;
    }
}

private void radGridView1_DragDrop(object sender, DragEventArgs e)
{
    GridViewRowInfo newRow = this.radGridView1.Rows.AddNew();
    newRow.Cells[0].Value = e.Data.GetData(typeof(string));
}

private void radTreeView1_MouseDown(object sender, MouseEventArgs e)
{
    RadTreeNode clickedNode = this.radTreeView1.GetNodeAt(e.X, e.Y);
    if (clickedNode != null)
    {
        this.DoDragDrop(clickedNode.Text, DragDropEffects.Copy);
    }
}

Basically the logic above copies the text from the dragged node and creates a new row in RadGridView assuming that the first column is GridViewTextBoxColumn. You can extend this example and use a custom data object which can contain all the necessary data to be transferred (not just the node text).

As to the drag and drop framework, we decided that it is not essential to implement one yet since we have other priorities(code base stability and documentation) and that the standard drag and drop mechanism is easy enough to use. Write again if you need further assistance.

Sincerely yours,
Victor
the Telerik team

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[Jay]

Sorry for the late reply but was just able to get back onto this project.

it works great!

thanks for the posted code.

Jay

[John Benny]

hi

I am writing C# win form.
I have created user control for RadGrid and created one more usercontrol for RadTreeview.  I am using both these
user control in my form. I need to drag item from grid to Tree view. How to do this? and How to raise these events.
Please let me kow.

regards,
John

[Nikolay]

Hi John Benny,

Could you please elaborate a bit more on the issues that you encounter? I am not sure that I undestand your question about raising the events.

You can refer to the solutions that my colleagues Jordan and Victor have given in this forum thread. These snippets are tested and as you can see they are working for our clients. So, it should be something specific in your case that prevents you from using these solutions.

Sincerely yours,
Nikolay
the Telerik team

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[John Benny]

hi,

Thanks for your response.

Sorry, it is my mistake. After i removed couple of code in my application, events is working fine.

Thanks,

John