TAdvTreeView + DragMode

[Martin_Pa]

Hello,

please I need a help how to proper work with TreeView when the DragMode is set to dmAutomatic. In this case I cannot expand the nodes by click to plus sign (+), the mouse event are not triggered (MouseDown nor NodeClick).

What I need is drag node and drop into button and show node's caption onto Button's. I was not sucessfull with "interaction - dragMode" property, so please could you help me how to handle this situation?

• When I set DragMode = dmAutomatic, I can handle drag'n'drop events and everithig is fine, but the TreeView is not working (selecting, expanding)

• When I set DragMode = dmManual, the TreeView behaviour is fine, but drag'n'drop is not working.

thanks in advice,
Ondrej.

[Pieter_Scheldeman (Pieter)]

Hi,

A complete sample can be found here, and involves assigning events to the custom drag/drop events:

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, AdvCustomControl, AdvTreeViewBase,
  AdvTreeViewData, AdvCustomTreeView, AdvTreeView, Types;

type
  TForm1 = class(TForm)
    AdvTreeView1: TAdvTreeView;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  procedure DoCustomDragOver(Sender: TObject; Source: TObject; Point: TPointF; var Accept: Boolean);
  procedure DoCustomDragDrop(Sender: TObject; Source: TObject; Point: TPointF);

  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.DoCustomDragDrop(Sender, Source: TObject; Point: TPointF);
var
  n: TAdvTreeViewVirtualNode;
begin
  if Source is TAdvTreeView then
  begin
    n := (Sender as TAdvTreeView).XYToNode(Point.X, Point.Y);
    if Assigned(n) and Assigned(n.node) and
      Assigned((Source as TAdvTreeView).DragNode) and Assigned((Source as TAdvTreeView).DragNode.Node) then
    begin
      n.Node.Nodes.Add.Assign((Source as TAdvTreeView).DragNode.Node);
    end;
  end;
end;

procedure TForm1.DoCustomDragOver(Sender, Source: TObject; Point: TPointF;
  var Accept: Boolean);
begin
  Accept := Source is TAdvTreeView;
end;

procedure TForm18.FormCreate(Sender: TObject);
begin
  AdvTreeView1.Interaction.DragDropMode := tdmCopy;
  AdvTreeView1.OnCustomDragOver := DoCustomDragOver;
  AdvTreeView1.OnCustomDragDrop := DoCustomDragDrop;
end;

end.

[Martin_Pa]

Hi Peter,

Wooow. Thanks, it works like a charm. Anyway, i see limitation that I can drag only "selected" node, not node which is currently "hot" (XYgetNode).

Thats strict limitation or we can do some similar charm :-)

thanks in advice, Ondrej

[Pieter_Scheldeman (Pieter)]

This can be achieved by selecting the node in the mousedown event:

procedure TForm18.AdvTreeView1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  n: TAdvTreeViewVirtualNode;
begin
  n := AdvTreeView1.XYToNode(X, Y);
  if Assigned(n) then
    AdvTreeView1.SelectNode(n.Node);
end;