您可以向DTM_SETSYSTEMTIMEDTP 发送消息HWND.但是,该消息将指向SYSTEMTIME记录的指针作为参数,并且该指针必须在拥有DTP控件的进程的地址空间中有效.
DTM_SETSYSTEMTIME是不是当跨进程边界发送的,所以如果你用一个指针指向一个由Windows自动编组SYSTEMTIME由发送进程所拥有并把它作为,是为DTP过程中,这是行不通的.您必须手动将SYSTEMTIME数据封送到DTP进程,例如:
uses
..., CommCtrl;
var
Wnd: HWND;
Pid: DWORD;
hProcess: THandle;
ST: TSystemTime;
PST: PSystemTime;
Written: SIZE_T;
begin
Wnd := ...; // the HWND of the DateTimePicker control
DateTimeToSystemTime(..., ST); // the desired date/time value
// open a handle to the DTP's owning process...
GetWindowThreadProcessId(Wnd, Pid);
hProcess := OpenProcess(PROCESS_VM_WRITE or PROCESS_VM_OPERATION, FALSE, Pid);
if hProcess = 0 then RaiseLastOSError;
try
// allocate a SYSTEMTIME record within the address space of the DTP process...
PST := PSystemTime(VirtualAllocEx(hProcess, nil, SizeOf(ST), MEM_COMMIT, PAGE_READWRITE));
if PST = nil then RaiseLastOSError;
try
// copy the SYSTEMTIME data into the DTP process...
if not WriteProcessMemory(hProcess, PST, @ST, SizeOf(ST), Written) then RaiseLastOSError;
// now send the DTP message, specifying the memory address that belongs to the DTP process...
SendMessage(Wnd, DTM_SETSYSTEMTIME, GDT_VALID, LPARAM(PST));
finally
// free the SYSTEMTIME memory...
VirtualFreeEx(hProcess, PST, SizeOf(ST), MEM_DECOMMIT);
end;
finally
// close the process handle...
CloseHandle(hProcess);
end;
end;
现在,有了这个说法,还有另一个问题TDateTimePicker(通常不是DTP控制). TDateTimePicker 不使用该DTM_GETSYSTEMTIME消息来检索当前选择的日期/时间.它的Date/ Time属性只返回在以下情况下TDateTime更新的内部变量的当前值:
的TDateTimePicker最初创建,其中的日期/时间被设定为Now().
其Date/ Time属性由应用程序分配,可以是代码或DFM流.
它会收到一个DTN_DATETIMECHANGE带有新日期/时间值的通知.
在这种情况下,你想要#3发生.但是,DTN_DATETIMECHANGE(基于WM_NOTIFY)不会自动生成DTM_SETSYSTEMTIME,因此您必须伪造它,但WM_NOTIFY 不能跨进程边界发送(Windows不允许它 - Raymond Chen 解释了一些原因).这在MSDN上有记录:
对于Windows 2000及更高版本的系统,无法在进程之间发送WM_NOTIFY消息.
因此,您必须在DTP拥有的进程中注入一些自定义代码,DTN_DATETIMECHANGE以便在与DTP相同的进程内发送.将代码注入另一个进程并不容易实现.然而,在这个特殊情况下,有一个相当简单的解决方案,礼貌David Ching:
https://groups.google.com/d/msg/microsoft.public.vc.mfc/QMAHlPpEQyM/Nu9iQycmEykJ
正如其他人指出的那样,LPARAM中的指针需要与创建hwnd的线程驻留在同一个进程中......我创建了一个SendMessageRemote()API,它使用VirtualAlloc,ReadProcessMemory,WriteProcessMemory和CreateRemoteThread来完成繁重的工作. ..
http://www.dcsoft.com/private/sendmessageremote.h
http://www.dcsoft.com/private/sendmessageremote.cpp它基于一篇很棒的CodeProject文章:
http://www.codeproject.com/threads/winspy.asp.
这是他的代码的Delphi翻译.注意,我已经在32位测试它,它的工作原理,但我没有在64位测试它.将消息从32位进程发送到64位进程或反之亦然,或者如果目标DTP使用的是Ansi窗口而不是Unicode窗口时,您可能需要调整它:
const
MAX_BUF_SIZE = 512;
type
LPFN_SENDMESSAGE = function(Wnd: HWND; Msg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
PINJDATA = ^INJDATA;
INJDATA = record
fnSendMessage: LPFN_SENDMESSAGE; // pointer to user32!SendMessage
hwnd: HWND;
msg: UINT;
wParam: WPARAM;
arrLPARAM: array[0..MAX_BUF_SIZE-1] of Byte;
end;
function ThreadFunc(pData: PINJDATA): DWORD; stdcall;
begin
Result := pData.fnSendMessage(pData.hwnd, pData.msg, pData.wParam, LPARAM(@pData.arrLPARAM));
end;
procedure AfterThreadFunc;
begin
end;
function SendMessageRemote(dwProcessId: DWORD; hwnd: HWND; msg: UINT; wParam: WPARAM; pLPARAM: Pointer; sizeLParam: size_t): LRESULT;
var
hProcess: THandle; // the handle of the remote process
hUser32: THandle;
DataLocal: INJDATA;
pDataRemote: PINJDATA; // the address (in the remote process) where INJDATA will be copied to;
pCodeRemote: Pointer; // the address (in the remote process) where ThreadFunc will be copied to;
hThread: THandle; // the handle to the thread executing the remote copy of ThreadFunc;
dwThreadId: DWORD;
dwNumBytesXferred: SIZE_T; // number of bytes written/read to/from the remote process;
cbCodeSize: Integer;
lSendMessageResult: DWORD;
begin
Result := $FFFFFFFF;
hUser32 := GetModuleHandle('user32');
if hUser32 = 0 then RaiseLastOSError;
// Initialize INJDATA
@DataLocal.fnSendMessage := GetProcAddress(hUser32, 'SendMessageW');
if not Assigned(DataLocal.fnSendMessage) then RaiseLastOSError;
DataLocal.hwnd := hwnd;
DataLocal.msg := msg;
DataLocal.wParam := wParam;
Assert(sizeLParam <= MAX_BUF_SIZE);
Move(pLPARAM^, DataLocal.arrLPARAM, sizeLParam);
// Copy INJDATA to Remote Process
hProcess := OpenProcess(PROCESS_CREATE_THREAD or PROCESS_QUERY_INFORMATION or PROCESS_VM_OPERATION or PROCESS_VM_WRITE or PROCESS_VM_READ, FALSE, dwProcessId);
if hProcess = 0 then RaiseLastOSError;
try
// 1. Allocate memory in the remote process for INJDATA
// 2. Write a copy of DataLocal to the allocated memory
pDataRemote := PINJDATA(VirtualAllocEx(hProcess, nil, sizeof(INJDATA), MEM_COMMIT, PAGE_READWRITE));
if pDataRemote = nil then RaiseLastOSError;
try
if not WriteProcessMemory(hProcess, pDataRemote, @DataLocal, sizeof(INJDATA), dwNumBytesXferred) then RaiseLastOSError;
// Calculate the number of bytes that ThreadFunc occupies
cbCodeSize := Integer(LPBYTE(@AfterThreadFunc) - LPBYTE(@ThreadFunc));
// 1. Allocate memory in the remote process for the injected ThreadFunc
// 2. Write a copy of ThreadFunc to the allocated memory
pCodeRemote := VirtualAllocEx(hProcess, nil, cbCodeSize, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
if pCodeRemote = nil then RaiseLastOSError;
try
if not WriteProcessMemory(hProcess, pCodeRemote, @ThreadFunc, cbCodeSize, dwNumBytesXferred) then RaiseLastOSError;
// Start execution of remote ThreadFunc
hThread := CreateRemoteThread(hProcess, nil, 0, pCodeRemote, pDataRemote, 0, dwThreadId);
if hThread = 0 then RaiseLastOSError;
try
WaitForSingleObject(hThread, INFINITE);
// Copy LPARAM back (result is in it)
if not ReadProcessMemory(hProcess, @pDataRemote.arrLPARAM, pLPARAM, sizeLParam, dwNumBytesXferred) then RaiseLastOSError;
finally
GetExitCodeThread(hThread, lSendMessageResult);
CloseHandle(hThread);
Result := lSendMessageResult;
end;
finally
VirtualFreeEx(hProcess, pCodeRemote, 0, MEM_RELEASE);
end;
finally
VirtualFreeEx(hProcess, pDataRemote, 0, MEM_RELEASE);
end;
finally
CloseHandle(hProcess);
end;
end;
现在,操作DTP的代码变得更加简单:
uses
..., CommCtrl;
var
Wnd: HWND;
Pid: DWORD;
nm: TNMDateTimeChange;
begin
Wnd := ...; // the HWND of the DateTimePicker control
// get PID of DTP's owning process
GetWindowThreadProcessId(Wnd, Pid);
// prepare DTP message data
nm.nmhdr.hwndFrom := Wnd;
nm.nmhdr.idFrom := GetDlgCtrlID(Wnd); // VCL does not use CtrlIDs, but just in case
nm.nmhdr.code := DTN_DATETIMECHANGE;
nm.dwFlags := GDT_VALID;
DateTimeToSystemTime(..., nm.st); // the desired date/time value
// now send the DTP messages from within the DTP process...
if SendMessageRemote(Pid, Wnd, DTM_SETSYSTEMTIME, GDT_VALID, @nm.st, SizeOf(nm.st)) <> 0 then
SendMessageRemote(Pid, GetParent(Wnd), WM_NOTIFY, nm.nmhdr.idFrom, @nm, sizeof(nm));
end;
如果一切顺利,TDateTimePicker现在将更新其内部TDateTime变量以匹配SYSTEMTIME您发送给它的内部变量.