鼠标的拖动操作

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Memo1: TMemo;
    procedure Edit1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Memo1DragOver(Sender, Source: TObject; X, Y: Integer;
      State: TDragState; var Accept: Boolean);
    procedure Memo1DragDrop(Sender, Source: TObject; X, Y: Integer);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Edit1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);                      //鼠标按下事件
begin
  if button = mbLeft then
    (sender as tedit).BeginDrag(false);                    //当单击鼠标左键并拖动一小段距离后才进行拖动操作
end;

procedure TForm1.Memo1DragDrop(Sender, Source: TObject; X, Y: Integer);
begin                                                      //停止拖动事件
  if (sender is tmemo) and (source is tedit) then
    (sender as tmemo).Lines.Add((source as tedit).Text);   //将编辑框中的内容添加到Memo组件的最后
end;

procedure TForm1.Memo1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);                 //鼠标拖动事件
begin
  if source is tedit then
    accept := true;                                        //可以接受拖动操作
end;

end.