unit sendunit;

interface

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

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Label1: TLabel;
    BitBtn1: TBitBtn;
    procedure BitBtn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    procedure SendData;
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
procedure TForm1.SendData; //發送消息和數據過程
var
Copydatastruct: TCopyDataStruct; //定義一個Tcopydatastruct類型的變量
hwnd: THandle; //句柄類型，用于存儲目標對象的句柄
begin 
Copydatastruct.cbData := Length (Edit1.Text) + 1; 

//為傳遞的數據區分配內存并把要傳送的字符串放入數據區
GetMem (Copydatastruct.lpData, Copydatastruct.cbData ); 
StrCopy (Copydatastruct.lpData, PChar (Edit1.Text)); 

// 獲得接收窗口的句柄
Hwnd := FindWindow (nil, '利用WM_COPYDATA進行數據交換演示Receive ');

// 如果目標對象存在，則向其發送WM_COPYDATA消息
if Hwnd <> 0 then 
SendMessage (Hwnd, WM_COPYDATA, Handle, Cardinal(@Copydatastruct)) 
else 
ShowMessage ('目標對象窗口沒找到！'); 

//釋放資源
FreeMem (Copydatastruct.lpData); 
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
begin
 if Edit1.Text<>'' then
  SendData;
end;

end.