Delphi Developer's Kit 1996/Delphi Developer's Kit 1996.iso/power/colbox/coolbox.pas

Pascal/Delphi Source File | 1995-12-22 | 5.0 KB | 149 lines

{A note from the author:

   I needed to do some spiffy things with the listboxes so I wrote this.  If it
already exists, then great, but I couldn't find it.  With this small program,
you can multi-select items from ListBox1 and drag them to ListBox2.
No big deal, except that you can INSERT a selected item into a specific spot
in the list.

   The really cool thing here is that you can select an item in ListBox2 and
move it into a another spot within the list by using the arrows or by dragging
and dropping.  Again, I couldn't find any code that already did this.  I hope
you find this code useful, and if you do any other cool things with it, please
let me know.  This code is only lightly documented, so if you have any
questions, jsut ask.  One reason for the length of this program is that
it is relatively (dare I say it?) bug-free.  I'll probably pay for that claim.

Richard Howard 71553,2544
Mei Technology Corporation
26 August 1995}

unit CoolBox;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, StdCtrls, Buttons;

type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    ListBox2: TListBox;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    procedure ListBox2DragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
    procedure ListBox2DragDrop(Sender, Source: TObject; X, Y: Integer);
    procedure ListBox2MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure ListBox1DragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
    procedure FormCreate(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  MoveSelectedItem : Integer; {the item in ListBox2 being moved}
  DnListBox1 : Boolean; {indicates which listbox to work with}
  DnListBox2 : Boolean; {indicates which listbox to work with}

implementation

{$R *.DFM}

procedure TForm1.ListBox2DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  if (Source is TListBox) then Accept := True;
  {because this is such a small program, 'ACCEPT := True' would work.  But
  larger programs need a little more control.}
end;

procedure TForm1.ListBox2DragDrop(Sender, Source: TObject; X, Y: Integer);
var
  i : Integer; {serves two purposes: 1) a counting variable for ListBox1,
               and 2) the item that the SELECTED item is being dropped on to
               in ListBox 2}
begin {procedure}
  {instructions for moving items from ListBox1 to ListBox2}
  if DnListBox1 then
  begin {if 1}
    for i := 0 to ListBox1.Items.Count - 1 do {look at ALL items in ListBox1}
    begin {for}
      if ListBox1.Selected[i] then
        ListBox2.Items.Insert(ListBox2.ItemAtPos(Point(X,Y), True)
          ,ListBox1.Items[i]);
        ListBox1.Selected[i] := False; {after copying to LB2, UNselect it}
    end; {for}
   DnListBox1 := False;
  end; {if 1}

  {instructions for moving an item WITHIN ListBox2}
  if DnListBox2 then
  begin {if 2}
    {i = the item UNDER the moving, selected item}
    i := ListBox2.ItemAtPos(Point(X, Y), True);
    ListBox2.Items.Move(MoveSelectedItem, i); {puts the moved item into place}
    ListBox2.ItemIndex := i; {select (highlight) the item you moved}
    if i = -1 then ListBox2.ItemIndex := ListBox2.Items.Count-1;
    DnListBox2 := False;
  end; {if 2}
end; {procedure}

procedure TForm1.ListBox2MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin {procedure}
  DnListBox1 := False;{tells the OnDragDrop procedure which instructions to use}
  DnListBox2 := True;{tells the OnDragDrop procedure which instructions to use}
  if Button = mbLeft then
    if ListBox2.ItemAtPos(Point(X, Y), True) >= 0 then
      MoveSelectedItem := ListBox2.ItemIndex;
end; {procedure}

procedure TForm1.ListBox1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  DnListBox1 := True;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  {I just threw these in here to look nice.  They can be pretty handy.}
  SendMessage(ListBox1.Handle, LB_SetHorizontalExtent, 1000, LongInt(0));
  SendMessage(ListBox2.Handle, LB_SetHorizontalExtent, 1000, LongInt(0));
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
var
  i : Integer;
begin {procedure}
  if ListBox2.ItemIndex > 0 then
  begin {if}
    i := ListBox2.ItemIndex;
    ListBox2.Items.Move(i, i-1);
    ListBox2.ItemIndex := i-1;
  end; {if}
end; {procedure}

procedure TForm1.BitBtn2Click(Sender: TObject);
var
  i : Integer;
begin {procedure}
  if (ListBox2.ItemIndex < ListBox2.Items.Count-1) and
     (ListBox2.ItemIndex <> -1) then
  begin {if}
    i := ListBox2.ItemIndex;
    ListBox2.Items.Move(i, i+1);
    ListBox2.ItemIndex := i+1;
  end; {if}
end; {procedure}

end.