unit1.~pas

Delphi 有很多很好的例子

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Panel1: TPanel;
    Memo2: TMemo;
    procedure MemoDragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.MemoDragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);

begin
Accept:=False;
if Source=Panel1 then begin
Accept:=True;
Memo1.Height:=Y+(Sender as TControl).Top;
end;

end;

end.