windows 在 Qt 应用程序中接收 WM_COPYDATA 消息
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Receive WM_COPYDATA messages in a Qt app
提问by andrewrk
I am working on a Windows-only Qt application, and I need to receive data from a Microsoft OneNote plugin. The plugin is written in C#, and can send WM_COPYDATA messages. How do I receive these messages in a C++ Qt app?
我正在开发一个仅限 Windows 的 Qt 应用程序，我需要从 Microsoft OneNote 插件接收数据。该插件是用 C# 编写的，可以发送 WM_COPYDATA 消息。如何在 C++ Qt 应用程序中接收这些消息？
I need to:
我需要：
- Be able to specify the "class name" a window registers as when it calls RegisterClassEx, so that I can make sure the plugin sends WM_COPYDATA messages to the correct window.
- Have access to the message id to check if it's WM_COPYDATA and lParam, which contains the COPYDATASTRUCT with the actual data. This information is passed in WndProc, but I am unable to find a hook where I can intercept these messages.
- 能够指定窗口在调用 RegisterClassEx 时注册的“类名”，以便我可以确保插件将 WM_COPYDATA 消息发送到正确的窗口。
- 有权访问消息 id 以检查它是否是 WM_COPYDATA 和 lParam，其中包含具有实际数据的 COPYDATASTRUCT。此信息在 WndProc 中传递，但我无法找到可以拦截这些消息的挂钩。
回答by andrewrk
This can all be handled within Qt:
这一切都可以在 Qt 中处理：
Extend QWidget with a class that will capture the WM_COPYDATA messages:
class EventReceiverWindow : public QWidget { Q_OBJECT public: EventReceiverWindow(); signals: void eventData(const QString & data); private: bool winEvent ( MSG * message, long * result ); };Generate a GUID to set as the QWidget's windowTitle:
EventReceiverWindow::EventReceiverWindow() { setWindowTitle("ProjectName-3F2504E0-4F89-11D3-9A0C-0305E82C3301::EventReceiver"); }Override winEvent to handle the WM_COPYDATA structure and emit a signal when you get it:
bool EventReceiverWindow::winEvent ( MSG * message, long * result ) { if( message->message == WM_COPYDATA ) { // extract the string from lParam COPYDATASTRUCT * data = (COPYDATASTRUCT *) message->lParam; emit eventData(QString::fromAscii((const char *)data->lpData, data->cbData)); // keep the event from qt *result = 0; return true; } // give the event to qt return false; }In another class, you can use this class to receive the message strings:
EventReceiverWindow * eventWindow = new EventReceiverWindow; QObject::connect(eventWindow, SIGNAL(eventData(const QString &)), this, SLOT(handleEventData(const QString &)));...
void OneNoteInterface::handleEventData(const QString &data) { qDebug() << "message from our secret agent: " << data; }And in the program that is sending the messages, simply find the windowby the unique window caption. Here's an example in C#:
private struct COPYDATASTRUCT { public IntPtr dwData; public int cbData; [MarshalAs(UnmanagedType.LPStr)] public string lpData; } private const int WM_COPYDATA = 0x4A; [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)] static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName); [DllImport("User32.dll", EntryPoint = "SendMessage")] private static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, ref COPYDATASTRUCT lParam); private void sendMessageTo(IntPtr hWnd, String msg) { int wParam = 0; int result = 0; if (hWnd != IntPtr.Zero ) { byte[] sarr = System.Text.Encoding.Default.GetBytes(msg); int len = sarr.Length; COPYDATASTRUCT cds; cds.dwData = IntPtr.Zero; cds.lpData = msg; cds.cbData = len + 1; result = SendMessage(hWnd, WM_COPYDATA, wParam, ref cds); } }then you can:
IntPtr hwnd = FindWindowByCaption(IntPtr.zero, "ProjectName-3F2504E0-4F89-11D3-9A0C-0305E82C3301::EventReceiver"); sendMessageTo(hwnd, "omg hai");
使用将捕获 WM_COPYDATA 消息的类扩展 QWidget：
class EventReceiverWindow : public QWidget { Q_OBJECT public: EventReceiverWindow(); signals: void eventData(const QString & data); private: bool winEvent ( MSG * message, long * result ); };生成一个 GUID 来设置为 QWidget 的 windowTitle：
EventReceiverWindow::EventReceiverWindow() { setWindowTitle("ProjectName-3F2504E0-4F89-11D3-9A0C-0305E82C3301::EventReceiver"); }覆盖 winEvent 以处理 WM_COPYDATA 结构并在获得它时发出信号：
bool EventReceiverWindow::winEvent ( MSG * message, long * result ) { if( message->message == WM_COPYDATA ) { // extract the string from lParam COPYDATASTRUCT * data = (COPYDATASTRUCT *) message->lParam; emit eventData(QString::fromAscii((const char *)data->lpData, data->cbData)); // keep the event from qt *result = 0; return true; } // give the event to qt return false; }在另一个类中，您可以使用此类来接收消息字符串：
EventReceiverWindow * eventWindow = new EventReceiverWindow; QObject::connect(eventWindow, SIGNAL(eventData(const QString &)), this, SLOT(handleEventData(const QString &)));...
void OneNoteInterface::handleEventData(const QString &data) { qDebug() << "message from our secret agent: " << data; }在发送消息的程序中，只需通过唯一的窗口标题找到窗口。这是 C# 中的一个示例：
private struct COPYDATASTRUCT { public IntPtr dwData; public int cbData; [MarshalAs(UnmanagedType.LPStr)] public string lpData; } private const int WM_COPYDATA = 0x4A; [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)] static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName); [DllImport("User32.dll", EntryPoint = "SendMessage")] private static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, ref COPYDATASTRUCT lParam); private void sendMessageTo(IntPtr hWnd, String msg) { int wParam = 0; int result = 0; if (hWnd != IntPtr.Zero ) { byte[] sarr = System.Text.Encoding.Default.GetBytes(msg); int len = sarr.Length; COPYDATASTRUCT cds; cds.dwData = IntPtr.Zero; cds.lpData = msg; cds.cbData = len + 1; result = SendMessage(hWnd, WM_COPYDATA, wParam, ref cds); } }然后你可以：
IntPtr hwnd = FindWindowByCaption(IntPtr.zero, "ProjectName-3F2504E0-4F89-11D3-9A0C-0305E82C3301::EventReceiver"); sendMessageTo(hwnd, "omg hai");
回答by OregonGhost
You can also create a dummy window just for receiving that message with the Win32 API. I guess you won't have access to a Qt-Window's window proc, so this should be the easiest way.
您还可以创建一个虚拟窗口，仅用于使用 Win32 API 接收该消息。我猜您将无法访问 Qt-Window 的窗口过程，所以这应该是最简单的方法。
You could(I wouldn't) also subclass the window by setting a new WndProc (with SetWindowLong(Ptr), the window's handle can be obtained with QWidget::winId()). In this WndProc, you could just handle your specific WM_COPYDATA and pass all other window messages to the old WndProc.
您也可以（我不会）通过设置一个新的 WndProc 来子类化窗口（使用SetWindowLong(Ptr)，可以使用 获得窗口的句柄QWidget::winId()）。在这个 WndProc 中，您可以只处理您的特定 WM_COPYDATA 并将所有其他窗口消息传递给旧的 WndProc。
回答by Idan K
To handle messages your window receives, override your QCoreApplication::winEventFilter. If that doesn't work you can take a look at QAbstractEventDispatcher.
要处理您的窗口收到的消息，请覆盖您的QCoreApplication::winEventFilter。如果这不起作用，您可以查看QAbstractEventDispatcher。
For the class name you could try using QWidget::winIdalong with Win32 API. I would try and find it for you but I can't right now, maybe try GetClassName.
对于类名，您可以尝试使用QWidget::winId和 Win32 API。我会尝试为您找到它，但我现在不能，也许尝试GetClassName。
