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Drag and Drop texto from a listbox to another showing the word being dragged.

Posted on 2013-12-04
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Last Modified: 2013-12-04
Hello,

I have a listbox1 with some words and a second empty listbox2. I can drag any word from listbox1 and drop it to listbox2, but the cursor is a drag figure and can't see the word that I am draging to the destination.

Is it possible to do it as it was made to picture? When I drag the image, I can pic it and it float with my cursor until the destination, can I do that with words?

pic drag from this thread http://www.experts-exchange.com/Programming/Languages/Pascal/Delphi/Q_28302574.html#a39695283

thanks
Alex
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Question by:hidrau
3 Comments
 
LVL 19

Accepted Solution

by:
Thommy earned 250 total points
ID: 39695643
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, jpeg, ExtCtrls;

type
  TForm1 = class(TForm)
    Image1: TImage;
    ListBox1: TListBox;
    ListBox2: TListBox;
    Label1: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure Image1DragDrop(Sender, Source: TObject; X, Y: Integer);
    procedure Image1DragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
    procedure ListBox2StartDrag(Sender: TObject; var DragObject: TDragObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  TTextDragObject = class(TDragControlObjectEx)
  private
    FDragImages: TDragImageList;
    FText: String;
  protected
    function GetDragImages: TDragImageList; override;
  end;


var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  ListBox2.DragMode := dmAutomatic;
  ControlStyle := ControlStyle + [csDisplayDragImage];
  Image1.ControlStyle := ListBox2.ControlStyle + [csDisplayDragImage];
end;

procedure TForm1.Image1DragDrop(Sender, Source: TObject; X, Y: Integer);
begin
  ListBox1.Items.Add(ListBox2.Items[ListBox2.Tag]);
end;

procedure TForm1.Image1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  Accept:=true;
end;


procedure TForm1.ListBox2StartDrag(Sender: TObject;
  var DragObject: TDragObject);
var
  List: TListbox absolute Sender;
begin
  DragObject := TTextDragObject.Create(List);
  if List.ItemIndex > -1 then
    TTextDragObject(DragObject).FText := List.Items[List.ItemIndex];
    List.Tag:=List.ItemIndex;
end;

function TTextDragObject.GetDragImages: TDragImageList;
var
  Bmp: TBitmap;
begin
  if FDragImages = nil then
  begin
    FDragImages := TDragImageList.Create(Control);
    Bmp := TBitmap.Create;
    try
      Bmp.Width := Bmp.Canvas.TextWidth(FText);
      Bmp.Height := Bmp.Canvas.TextHeight(FText);
      Bmp.Canvas.TextOut(0, 0, FText);
      FDragImages.Width := Bmp.Width;
      FDragImages.Height := Bmp.Height;
      FDragImages.SetDragImage(FDragImages.Add(Bmp, nil), 0, 0);
    finally
      Bmp.Free;
    end;
  end;
  Result := FDragImages;
end;


end.

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LVL 26

Assisted Solution

by:Sinisa Vuk
Sinisa Vuk earned 250 total points
ID: 39696634
My example is very similar. I use transparency in dragging text. Works as I described in another thread and Thommy did it similar too.

Thommy, small comment if I may - you didn't destroy your TDragImageList after usage.
drag.zip
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LVL 1

Author Closing Comment

by:hidrau
ID: 39697035
Thanks very much everybody
0

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