PostThreadMessage问题，知之者请入，不知者请看

Question

x-soft.myrice.com有一个WINDOWS ATOM的应用
可以是在各个PROGRAM见传输
你可以去看看
看过后应该就名了

Answer 1

呵呵,下面的代码你可以参考一下,思路就是在用自己的消息循环代替Application对象的消息循环
program Project1;uses
  windows,
  Messages,
  Forms,
  Unit1 in 'Unit1.pas' {Form1};{$R *.RES}
const
  WM_MY_CREATE_WINDOW = WM_USER + 100;var
  msg: TMsg;
begin
  Application.Initialize;
  while GetMessage(Msg, 0, 0, 0) do
  begin
     if Msg.message = WM_MY_CREATE_WINDOW then
     begin
       Application.CreateForm(TForm1, Form1);
     end;
  end;
  Application.Run;
end.

Answer 2

呵呵,忘了,
Application.CreateForm(TForm1, Form1);
下面要有还要 break;用来跳出循环!

Answer 3

to weizhi:
    有问题：当程序执行到GetMessage时便停住不动了，根本执行不到if判断那。

Answer 4

呵呵,你说的不错,用GetMessage就是这样的,当队列中没消息时,它就挂起线程了,当有消息时才会继续向下的执行的.
你可以改用PeekMessage就不会这样了

Answer 5

begin
  hMutex := CreateMutex(nil, False, 'MyProject');
  Ret := GetLastError;
  try
    if Ret = ERROR_ALREADY_EXISTS then
    begin
      SendMsg(WM_MY_CREATE_WINDOW);
    end
    else
    begin
      Application.Initialize;
      while not Application.Terminated do
      begin
        PeekMessage(Msg, 0, 0, 0, PM_REMOVE);
        if Msg.message = WM_MY_CREATE_WINDOW then
        begin
          ShowMessage('Application.CreateForm(TForm1, Form1);');
          Break;
        end;
      end;
    end;
  finally
    CloseHandle(hMutex);
  end;
end;function GetThreadId(ProcessName: string): THandle;
var
  SnapshotHandle: THandle;
  ProcessEntry: TProcessEntry32;
  ProcessID: DWORD;
  Next: Boolean;
  S: string;
begin
  ProcessId := 0;
  if OsIsNt then
  begin
    ProcessID := GetProcessID(ProcessName);
  end else begin
    SnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if SnapshotHandle <> THandle(-1) then
    begin
      ProcessEntry.dwSize := SizeOf(TProcessEntry32);
      Next := Process32First(SnapshotHandle, ProcessEntry);
      while Next do
      begin
        S := ExtractFileName(ProcessEntry.szExeFile);
        if CompareText(S, ProcessName) = 0 then
        begin
          ProcessID := ProcessEntry.th32ProcessID;
          Break;
        end;
        Next := Process32Next(SnapshotHandle, ProcessEntry);
      end;
      CloseHandle(SnapshotHandle);
    end;
  end;
  Result := ProcessID;
end;
procedure SendMsg(M: DWORD);
var
  ThreadId: DWORD;
begin
  ThreadId := GetThreadId(ExtractFileName(Application.ExeName));
  if ThreadId <> 0 then
  begin
    PostThreadMessage(ThreadId, M, 0, 0);
  end;
end;这样写还是没有反应，是代码有问题吗？？？GetThreadId得到的ThreadId与Application.Handle并不一样，是不是这个不一样的ThreadId导致了消息没有收到？？？？？

Answer 6

进程ID和线程ID是不同的,你应找到此进程的主线程ID才行!
可用Thread32First(), Thread32Next()找到你要的线程(通过线程的进程ID可识别),然后向此线程发消息

Answer 7

还有,你的程序中,退出循环后,可有Application.Run;用来将控制交给Application对象,由它处理后面的消息!否则,你退出循环后,程序就结束了!

Answer 8

你这样写了以后,在没有收到WM_MY_CREATE_WINDOW 之前,程序当然是没反应的,因为它在空的消息循环中嘛!

Answer 9

procedure SendMsg(M: DWORD);
var
  ThreadId: DWORD;
begin
  ThreadId := ProcessId(ExtractFileName(Application.ExeName));
  ThreadId := GetThreadId(ThreadId);
  if ThreadId <> 0 then
  begin
    PostThreadMessage(ThreadId, M, 0, 0);
  end;
end;function ProcessId(ProcessName: string): THandle;
var
  SnapshotHandle: THandle;
  ProcessEntry: TProcessEntry32;
  ProcessID: DWORD;
  Next: Boolean;
  S: string;
begin
  ProcessId := 0;
  if OsIsNt then
  begin
    ProcessID := GetProcessID(ProcessName);
  end else begin
    SnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if SnapshotHandle <> THandle(-1) then
    begin
      ProcessEntry.dwSize := SizeOf(TProcessEntry32);
      Next := Process32First(SnapshotHandle, ProcessEntry);
      while Next do
      begin
        S := ExtractFileName(ProcessEntry.szExeFile);
        if CompareText(S, ProcessName) = 0 then
        begin
          ProcessID := ProcessEntry.th32ProcessID;
          Break;
        end;
        Next := Process32Next(SnapshotHandle, ProcessEntry);
      end;
      CloseHandle(SnapshotHandle);
    end;
  end;
  Result := ProcessID;
end;function GetThreadId(ProcessID: DWORD): DWORD;
var
  SnapshotHandle: THandle;
  Thread32Entry: TThreadEntry32;
  ThreadId: DWORD;
  Next: Boolean;
begin
  ThreadId := 0;
  SnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
  if SnapshotHandle <> THandle(-1) then
  begin
    Thread32Entry.dwSize := SizeOf(TThreadEntry32);
    Next := Thread32First(SnapshotHandle, Thread32Entry);
    while Next do
    begin
      if Thread32Entry.th32OwnerProcessID = ProcessId then
      begin
        ThreadId := Thread32Entry.th32ThreadID;
        Break;
      end;
      Next := Thread32Next(SnapshotHandle, Thread32Entry);
    end;
    CloseHandle(SnapshotHandle);
  end;
  Result := ThreadId;
end;  hMutex := CreateMutex(nil, False, 'MyProject');
  Ret := GetLastError;
  try
    if Ret = ERROR_ALREADY_EXISTS then
    begin
      SendMsg(WM_MY_CREATE_WINDOW);
    end
    else
    begin
      Application.Initialize;
      while True {GetMessage(Msg, 0, 0, 0)} do
      begin
        PeekMessage(Msg, 0, 0, 0, PM_REMOVE);
        if Msg.message = WM_MY_CREATE_WINDOW then
        begin
          if Form1 = nil then
            Application.CreateForm(TForm1, Form1);
          Break;
        end;
      end;
    end;
    Application.Run;
  finally
    CloseHandle(hMutex);
  end;成功，散分