C#与C++通信

# C#与C++相互发送消息 #

## C#端： ##

namespace CshapMessage
{
///

/// MainWindow.xaml 的交互逻辑
///

public partial class MainWindow : Window
{
IntPtr hwnd;

const int WM_COPYDATA = 0x004A;

public struct COPYDATASTRUCT
{
public IntPtr dwData;
public int cData;
[MarshalAs(UnmanagedType.LPStr)]
public string lpData;
}

[DllImport("User32.dll")]
public static extern int SendMessage(int hwnd, int msg, int wParam, ref COPYDATASTRUCT IParam);
[DllImport("User32.dll")]
public static extern int FindWindow(string lpClassName, string lpWindowName);

public MainWindow()
{
InitializeComponent();
this.Title = "CshapMessage";
this.Loaded += MainWindow_Loaded;
this.Closed += MainWindow_Closed;
}

private void MainWindow_Closed(object sender, EventArgs e)
{
try
{
HwndSource.FromHwnd(hwnd).RemoveHook(WndProc);
}
catch (Exception) { }
}

private void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
hwnd = new WindowInteropHelper(this).Handle;
HwndSource.FromHwnd(hwnd).AddHook(new HwndSourceHook(WndProc));
}

///

/// 向C++程序 CshapMessage发送消息
///

///
///
///
private bool CshapSendMessage(int nMessgeId, String strSend)
{
int WINDOW_HANDLE = FindWindow(null, "VcMessage");//VcMessage为向C++程序发送的窗口名称
if (WINDOW_HANDLE != 0)
{
COPYDATASTRUCT cdata;
cdata.dwData = (IntPtr)100;//这里可以传入一些自定义的数据，但只能是4字节整数
cdata.lpData = strSend;//消息字符串
cdata.cData = System.Text.Encoding.Default.GetBytes(strSend).Length+1;//注意，这里的长度是按字节来算的

SendMessage(WINDOW_HANDLE, WM_COPYDATA, 0, ref cdata);
}
else
{
return false;
}
return true;
}

private void button_Click(object sender, RoutedEventArgs e)
{
String strSend = "C#发送的信息";
int nMessageId = 100;

if (CshapSendMessage(nMessageId,strSend))
{
MessageBox.Show("发送消息成功");
}
else
{
MessageBox.Show("消息发送失败，请打开VcMessage程序");
}
}

//接收消息。
private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
if (msg == WM_COPYDATA)
{
COPYDATASTRUCT cdata = new COPYDATASTRUCT();
Type mytype = cdata.GetType();
cdata = (COPYDATASTRUCT)Marshal.PtrToStructure(lParam, mytype);
switch (cdata.dwData.ToInt32())
{
case 1:
{
string strRecv = cdata.lpData;
break;
}
default:
break;
}
}

return IntPtr.Zero;
}
}
}

## C++端： ##

BOOL CVcMessageDlg::OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值

//接收C#发送来的数据
switch (pCopyDataStruct->dwData)
{
case 100:
{
CStringA strRecv = (char*)pCopyDataStruct->lpData;
break;
}

default:
{
break;
}
}

return CDialogEx::OnCopyData(pWnd, pCopyDataStruct);
}

void CVcMessageDlg::OnBnClickedButton1()
{
// TODO: 在此添加控件通知处理程序代码

CStringA strSend = "VC发送的数据";

if (VCSendMessage(1,strSend))
{
AfxMessageBox(_T("消息发送成功"));
}
else
{
AfxMessageBox(_T("消息发送失败"));
}
}

//************************************
// Method: VCSendMessage
// FullName: CVcMessageDlg::VCSendMessage
// Access: public
// Returns: BOOL
// Qualifier: 向C#程序 CshapMessage发送消息
// Parameter: int nMessgeId
// Parameter: CStringA strSend
//************************************
BOOL CVcMessageDlg::VCSendMessage(int nMessgeId,CStringA strSend)
{
HWND hSendWindow = this->m_hWnd;
if (hSendWindow == NULL)
{
return FALSE;
}

CWnd *phwnd = FindWindow(NULL, _T("CshapMessage"));
HWND hRecvWindow = NULL;
if (phwnd == NULL)
{
return FALSE;
}

hRecvWindow = phwnd->GetSafeHwnd();

if (hRecvWindow == NULL)
{
return FALSE;
}

COPYDATASTRUCT CopyData;
CopyData.dwData = nMessgeId;
CopyData.cbData = strSend.GetLength()+1;
CopyData.lpData = (PVOID)strSend.GetBuffer(CopyData.cbData);

::SendMessage(hRecvWindow, WM_COPYDATA, (WPARAM)hSendWindow, (LPARAM)&CopyData);

return TRUE;
}