WM_COPYDATA是一个非常特殊的消息，此消息可能携带一个比较大的消息参数，而其他消息都只能携带两个固定大小的参数(WPARAM和LPARAM)。
在发送WM_COPYDATA消息时，WM_COPYDATA的wParam参数应该赋值为发送此消息的窗口，而lParam消息参数指向一个COPYDATASTRUCT结构类型的变量。
typedef struct tagCOPYDATASTRUCT {
ULONG_PTR dwData;
DWORD cbData;
PVOID lpData;
} COPYDATASTRUCT, *PCOPYDATASTRUCT;
dwData可以是任意值，lpData是需要发送给目录窗口所在进程的数据，cbData字符指定了lpData内存区域的字节数，也就是需要发送给目标进程的lpData所指向的数据的大小。
在消息发送时，系统会将整个COPYDATASTRUCT及lpData所指向的内容全部发送给目标进程。目标进程窗口在收到WM_COPYDATA后，可以从lParam参数中提取出数据。
1、一个例子
数据发送端
通过WM_COPYDATA进程间通信-发送端
通过WM_COPYDATA进程间通信
**************************************/
/* 头文件 */
#include <windows.h>
#include <commctrl.h>
#include "resource.h"
/* 全局变量 */
HINSTANCE hinst;
HWND hwnd, hwndEdit;
LPSTR lpszCopy = "you can input any text\n then click \'Send\' Item at Menu";
/* 函数声明 */
int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int);
LRESULT CALLBACK MainWndProc(HWND, UINT, WPARAM, LPARAM);
/* ************************************
* WinMain
**************************************/
int WINAPI WinMain(
HINSTANCE hinstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
MSG msg;
WNDCLASSEX wcx;
hinst = hinstance; // 保存应用程序实例
// 填充WNDCLASSEX
wcx.cbSize = sizeof(wcx);
wcx.style = CS_HREDRAW | CS_VREDRAW;
wcx.lpfnWndProc = MainWndProc; // 消息处理函数
wcx.cbClsExtra = 0;
wcx.cbWndExtra = 0;
wcx.hInstance = hinstance;
wcx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wcx.hCursor = LoadCursor(NULL, IDC_ARROW);
wcx.hbrBackground = (HBRUSH)GetStockObject( WHITE_BRUSH);
wcx.lpszMenuName = MAKEINTRESOURCE(IDR_MENU_COMMAND); // 菜单
wcx.lpszClassName = "copydata"; // 窗口类名
wcx.hIconSm = NULL;
// 注册窗口类
if(RegisterClassEx(&wcx) == 0)
{
return 0;
}
// 创建窗口
hwnd = CreateWindow(
"copydata",
"Sample",
WS_TILEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 500, 400,
(HWND) NULL,
(HMENU) NULL,
hinstance,
(LPVOID) NULL);
if (!hwnd)
return 0;
// 显示、刷新窗口
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// 消息循环
BOOL fGotMessage;
while ((fGotMessage = GetMessage(&msg, (HWND) NULL, 0, 0)) != 0 && fGotMessage != -1)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
UNREFERENCED_PARAMETER(lpCmdLine);
}
/* ************************************
* 消息处理函数
**************************************/
LONG APIENTRY MainWndProc(HWND hwnd,
UINT message,
WPARAM wParam,
LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
{
// 在主窗口创建时，创建一个EDIT控件，用于编辑需要复制的内容
RECT rectMain;
GetClientRect(hwnd,&rectMain);
hwndEdit = CreateWindow("EDIT",
NULL,
WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_BORDER |
ES_LEFT | ES_MULTILINE | ES_AUTOVSCROLL,
0., 0, rectMain.right, rectMain.bottom,
hwnd, NULL,
(HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE),
NULL);
if(hwndEdit == NULL)
{
MessageBox(hwnd, "Create Window Error","ERROR",MB_OK);
ExitProcess(0);
}
// 设置EDIT控件的内容
SendMessage(hwndEdit, WM_SETTEXT, 0, (LPARAM) lpszCopy);
break;
}
case WM_COMMAND: // 菜单输入
{
// 如果通过菜单点击“send”按钮
if (LOWORD(wParam) == ID_COMMAND_SEND)
{
// 获取EDIT控件中的文本
DWORD dwTextLenth = GetWindowTextLength(hwndEdit);
LPSTR szText = (LPSTR)HeapAlloc(GetProcessHeap(),HEAP_NO_SERIALIZE,dwTextLenth);
GetWindowText(hwndEdit,szText,dwTextLenth);
// 构造 COPYDATASTRUCT
COPYDATASTRUCT cds;
HWND hwnd2 = FindWindow("copydata2","RECV COPY DATA");
if(hwnd2 == NULL)
{
MessageBox(hwnd,"can not find window 2","ERROR",MB_OK);
break;
}
cds.dwData = 0x12345678; // 自定义的数据
cds.cbData = dwTextLenth; // lpData的长度
cds.lpData = szText; // 需要复制的数据
// 发送消息，COPYDATASTRUCT结构的指针做为lParam
SendMessage(
hwnd2, // 目的窗口
(UINT) WM_COPYDATA, // 消息 ID
(WPARAM) hwnd, // wParam，源窗口句柄
(LPARAM) &cds // lParam，COPYDATASTRUCT
);
// 释放内存
HeapFree(GetProcessHeap(),HEAP_NO_SERIALIZE,szText);
}
break;
}
case WM_DESTROY: // 退出
PostQuitMessage(0);
return 0;
default: // 其他消息的处理
return DefWindowProc(hwnd, message, wParam, lParam);
}
return 0;
}
数据接收端
通过WM_COPYDATA进程间通信－接收端
通过WM_COPYDATA进程间通信
**************************************/
/* 头文件 */
#include <windows.h>
#include <commctrl.h>
/* 全局变量 */
HINSTANCE hinst;
HWND hwnd,hwndEdit;
/* 函数声明 */
int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int);
LRESULT CALLBACK MainWndProc(HWND, UINT, WPARAM, LPARAM);
/* ************************************
* void main()
* 功能 进程间mailslot通信客户端
**************************************/
int WINAPI WinMain(
HINSTANCE hinstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
MSG msg;
WNDCLASSEX wcx;
// 填充WNDCLASSEX
wcx.cbSize = sizeof(wcx);
wcx.style = CS_HREDRAW | CS_VREDRAW;
wcx.lpfnWndProc = MainWndProc;
wcx.cbClsExtra = 0;
wcx.cbWndExtra = 0;
wcx.hInstance = hinstance;
wcx.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wcx.hCursor = LoadCursor(NULL, IDC_ARROW);
wcx.hbrBackground = (HBRUSH)GetStockObject( WHITE_BRUSH);
wcx.lpszMenuName = NULL;
wcx.lpszClassName = "copydata2";
wcx.hIconSm = NULL;
// 注册窗口类
if(RegisterClassEx(&wcx) == 0)
{
return 0;
}
// 创建窗口
hwnd = CreateWindow(
"copydata2",
"RECV COPY DATA",
WS_TILEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 500, 400,
(HWND) NULL, (HMENU) NULL, hinstance, (LPVOID) NULL
);
if (!hwnd)
return 0;
// 显示刷新窗口
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// 消息
BOOL fGotMessage;
while ((fGotMessage = GetMessage(&msg, (HWND) NULL, 0, 0)) != 0 && fGotMessage != -1)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
UNREFERENCED_PARAMETER(lpCmdLine);
return 0;
}
// 消息处理函数
LONG APIENTRY MainWndProc(HWND hwnd,
UINT message,
WPARAM wParam,
LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
{
// 创建主窗口时，创建一个EDIT控件
RECT rectMain;
GetClientRect(hwnd,&rectMain);
hwndEdit = CreateWindow("EDIT",
NULL,
WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_BORDER |
ES_LEFT | ES_MULTILINE | ES_AUTOVSCROLL,
0., 0, rectMain.right, rectMain.bottom,
hwnd,
NULL,
(HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE),
NULL);
if(hwndEdit == NULL)
{
MessageBox(hwnd, "Create Window Error","ERROR",MB_OK);
ExitProcess(0);
}
break;
case WM_COPYDATA:
{
// 当收到WM_COPYDATA消息时，从lParam中提取出
// COPYDATASTRUCT
PCOPYDATASTRUCT lpcds = (PCOPYDATASTRUCT)lParam;
// 将复制的数据在界面上显示
SetWindowText(hwndEdit,(LPSTR)lpcds->lpData);
break;
}
case WM_DESTROY: // 退出
PostQuitMessage(0);
return 0;
default: // 其他消息处理
break;
}
}
return DefWindowProc(hwnd, message, wParam, lParam);
}
Interprocess Communications[2]
参考
