Delphi 版的两种常用进程间消息通信示例：WM_COPYDATA 和命名管道（Named Pipe）

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下面给出 Delphi 版的两种常用进程间消息通信示例：WM_COPYDATA 和命名管道（Named Pipe）。

WM_COPYDATA（小块数据/文本，窗口间）

uses Windows, Messages, SysUtils;
type
TMainForm = class(TForm)
private
procedure WMCopyData(var Msg: TWMCopyData); message WM_COPYDATA;
end;
procedure TMainForm.WMCopyData(var Msg: TWMCopyData);
var
S: AnsiString;
begin
if (Msg.CopyDataStruct <> nil) and (Msg.CopyDataStruct.cbData > 0) then
begin
SetString(S, PAnsiChar(Msg.CopyDataStruct.lpData), Msg.CopyDataStruct.cbData - 1);
OutputDebugString(PChar('Recv: ' + string(S)));
Msg.Result := 1;
end
else
Msg.Result := 0;
end;
// 发送端
procedure SendIpc(const TargetClass, TargetCaption: string; const Text: AnsiString);
var
H: HWND;
CDS: TCopyDataStruct;
begin
H := FindWindow(PChar(TargetClass), PChar(TargetCaption));
if H <> 0 then
begin
CDS.dwData := 1; // 自定义标识
CDS.cbData := Length(Text) + 1; // 包含结尾 #0
CDS.lpData := PAnsiChar(Text);
SendMessage(H, WM_COPYDATA, 0, LPARAM(@CDS));
end;
end;

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命名管道（双向、可发较大量数据）

uses Windows, SysUtils, Classes;
const
PIPE_NAME = '\\.\pipe\MyPipe';
procedure PipeServer;
var
hPipe: THandle;
Buf: array[0..1023] of AnsiChar;
ReadBytes, Written: DWORD;
Reply: AnsiString;
begin
while True do
begin
hPipe := CreateNamedPipe(PChar(PIPE_NAME),
PIPE_ACCESS_DUPLEX,
PIPE_TYPE_BYTE or PIPE_READMODE_BYTE or PIPE_WAIT,
PIPE_UNLIMITED_INSTANCES, 4096, 4096, 0, nil);
if hPipe = INVALID_HANDLE_VALUE then Exit;
if ConnectNamedPipe(hPipe, nil) or (GetLastError = ERROR_PIPE_CONNECTED) then
begin
if ReadFile(hPipe, Buf, SizeOf(Buf) - 1, ReadBytes, nil) then
begin
Buf[ReadBytes] := #0;
OutputDebugString(PChar('Server recv: ' + string(AnsiString(Buf))));
Reply := 'ACK';
if Length(Reply) > 0 then
WriteFile(hPipe, Reply[1], Length(Reply), Written, nil);
end;
FlushFileBuffers(hPipe);
DisconnectNamedPipe(hPipe);
end;
CloseHandle(hPipe);
end;
end;
procedure StartPipeServer;
begin
TThread.CreateAnonymousThread(
procedure
begin
PipeServer;
end).Start;
end;
// 客户端
function PipeClientSend(const Msg: AnsiString): Boolean;
var
h: THandle;
Wrote, ReadBytes: DWORD;
Buf: array[0..1023] of AnsiChar;
begin
Result := False;
if not WaitNamedPipe(PChar(PIPE_NAME), 5000) then Exit;
h := CreateFile(PChar(PIPE_NAME), GENERIC_READ or GENERIC_WRITE, 0, nil,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
if h = INVALID_HANDLE_VALUE then Exit;
try
if Length(Msg) > 0 then
WriteFile(h, Msg[1], Length(Msg), Wrote, nil);
if ReadFile(h, Buf, SizeOf(Buf) - 1, ReadBytes, nil) then
begin
Buf[ReadBytes] := #0;
OutputDebugString(PChar('Client recv: ' + string(AnsiString(Buf))));
Result := True;
end;
finally
CloseHandle(h);
end;
end;

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要点

WM_COPYDATA 适合同机窗口间小数据；命名管道更通用、可双向收发。
Delphi 新版 String 为 Unicode；通过 AnsiString 携带字节并用 PAnsiChar 传输更稳。

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Delphi 版的两种常用进程间消息通信示例：WM_COPYDATA 和命名管道（Named Pipe）

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