K210.ORG

unit Unit1;

 

interface

 

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, ComCtrls;

 

type

  TForm1 = class(TForm)

    TreeView1: TTreeView;

    procedure TreeView1DragDrop(Sender, Source: TObject; X, Y: Integer);

    procedure TreeView1StartDrag(Sender: TObject;

      var DragObject: TDragObject);

    procedure TreeView1DragOver(Sender, Source: TObject; X, Y: Integer;

      State: TDragState; var Accept: Boolean);

    procedure FormCreate(Sender: TObject);

  private

    FDraggedItem: TTreeNode;

 

    { Private declarations }

  public

    { Public declarations }

  end;

 

var

  Form1: TForm1;

 

implementation

 

{$R *.dfm}

 

procedure TForm1.TreeView1DragDrop(Sender, Source: TObject; X, Y: Integer);

var

  FTargetItem: TTreeNode;

begin

  FTargetItem := treeview1.GetNodeAt(x, y);

  if Assigned(FTargetItem) then begin

    if GetKeyState(VK_SHIFT) < 0 then

      // If Shift is down make dragged node a child of the target node

      FDraggedItem.MoveTo(FTargetItem, naAddChildFirst)

    else

      // Make dragged node a sibling of the target node

      if FTargetItem.getNextSibling <> nil then

        FDraggedItem.MoveTo(FTargetItem.getNextSibling, naInsert)

      else

        FDraggedItem.MoveTo(FTargetItem, naAdd);

  end

  else begin

    if y < 5 then begin

      // Make dragged node the first root node

      if treeview1.Items[0] <> FDraggedItem then

        FDraggedItem.MoveTo(treeview1.Items[0], naInsert);

    end

    else

      // Make dragged node the last root node

      FDraggedItem.MoveTo(treeview1.Items[0], naAdd);

  end;

  FDraggedItem := nil;

 

end;

 

procedure TForm1.TreeView1StartDrag(Sender: TObject;

  var DragObject: TDragObject);

var

  pt: TPoint;

begin

  pt := treeview1.ScreenToClient(mouse.cursorpos);

  FDraggedItem := treeview1.GetNodeAt(pt.x, pt.y);

  if not Assigned(FDraggedItem) then

    CancelDrag;

end;

 

 

procedure TForm1.TreeView1DragOver(Sender, Source: TObject; X, Y: Integer;

  State: TDragState; var Accept: Boolean);

begin

  Accept := (sender = source) and

    (FDraggedItem <> treeview1.GetNodeAt(x, y));

end;

 

procedure TForm1.FormCreate(Sender: TObject);

var

  node: TTreenode;

  i, j: integer;

begin

  for i := 1 to 10 do begin

    node := TreeView1.Items.Add(nil, inttostr(i));

    for j := 1 to 3 do

      node := TreeView1.Items.AddChild(node, inttostr(i) + '->sub' + inttostr(j));

  end;

end;

 

end.