, (streams)




{
The WM_COPYDATA messages makes it possible to transfer information
between processes. It does this by passing the data through the kernel.
Space is allocated in the receiving process to hold the information that is copied,
by the kernel, from the source process to the target process.
The sender passes a pointer to a COPYDATASTRUCT, which is defined as a structure
of the following:
}
type
TCopyDataStruct = packed record
dwData: DWORD;   // anwendungsspezifischer Wert 
cbData: DWORD;   // Byte-Lnge der zu bertragenden Daten 
lpData: Pointer; // Adresse der Daten 
end;
{ Sender Application }
unit SenderApp;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ExtCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Edit1: TEdit;
Button2: TButton;
Image1: TImage;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
procedure SendCopyData(hTargetWnd: HWND; ACopyDataStruct:TCopyDataStruct);
public
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
// Sender: Send data 
procedure TForm1.SendCopyData(hTargetWnd: HWND; ACopyDataStruct:TCopyDataStruct);
begin
if hTargetWnd <> 0 then
SendMessage(hTargetWnd, WM_COPYDATA, Longint(Handle), Longint(@ACopyDataStruct))
else
ShowMessage('No Recipient found!');
end;
// Send Text from Edit1 to other app 
procedure TForm1.Button1Click(Sender: TObject);
var
MyCopyDataStruct: TCopyDataStruct;
hTargetWnd: HWND;
begin
// Set up a COPYDATASTRUCT structure for use with WM_COPYDATA 
// TCopyDataStruct mit den Sende-Daten Infos ausfllen 
with MyCopyDataStruct do
begin
dwData := 0; // may use a value do identify content of message 
cbData := StrLen(PChar(Edit1.Text)) + 1;  //Need to transfer terminating #0 as well 
lpData := PChar(Edit1.Text)
end;
// Find the destination window for the WM_COPYDATA message 
// Empfnger Fenster anhand des Titelzeilentextes suchen 
hTargetWnd := FindWindow(nil,PChar('Message Receiver'));
// send the structure to the receiver 
// Die Struktur an den Empfnger schicken 
SendCopyData(hTargetWnd, MyCopyDataStruct);
end;
// Send Image1 to other app 
procedure TForm1.Button2Click(Sender: TObject);
var
ms: TMemoryStream;
MyCopyDataStruct: TCopyDataStruct;
hTargetWnd: HWND;
begin
ms := TMemoryStream.Create;
try
image1.Picture.Bitmap.SaveToStream(ms);
with MyCopyDataStruct do
begin
dwData := 1;
cbData := ms.Size;
lpData := ms.Memory;
end;
// Search window by the window title 
// Empfnger Fenster anhand des Titelzeilentextes suchen 
hTargetWnd := FindWindow(nil,PChar('Message Receiver'));
// Send the Data 
// Daten Senden 
SendCopyData(hTargetWnd,MyCopyDataStruct);
finally
ms.Free;
end;
end;
end.
{*********************************************************************}
{ Receiver Application }
unit ReceiverApp;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls, StdCtrls;
type
TForm1 = class(TForm)
Image1: TImage;
Label1: TLabel;
private
procedure WMCopyData(var Msg: TWMCopyData); message WM_COPYDATA;
{ Private-Deklarationen }
public
{ Public-Deklarationen }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.WMCopyData(var Msg: TWMCopyData);
var
sText: array[0..99] of Char;
ms: TMemoryStream;
begin
case Msg.CopyDataStruct.dwData of
0: { Receive Text, Text empfangen}
begin
StrLCopy(sText, Msg.CopyDataStruct.lpData, Msg.CopyDataStruct.cbData);
label1.Caption := sText;
end;
1: { Receive Image, Bild empfangen}
begin
ms := TMemoryStream.Create;
try
with Msg.CopyDataStruct^ do
ms.Write(lpdata^, cbdata);
ms.Position := 0;
image1.Picture.Bitmap.LoadFromStream(ms);
finally
ms.Free;
end;
end;
end;
end;
end.


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