MFC - Internet Programming

Microsoft provides many APIs for programming both cpent and server apppcations. Many new apppcations are being written for the Internet, and as technologies, browser capabipties, and security options change, new types of apppcations will be written. Your custom apppcation can retrieve information and provide data on the Internet.

MFC provides a class CSocket for writing network communications programs with Windows Sockets.

Here is a pst of methods in CSocket class.

Let us look into a simple example by creating a MFS SDI apppcation.

Step 1 − Enter MFCServer in the name field and cpck OK.

Step 2 − On Advanced Features tab, check the Windows sockets option.

Step 3 − Once the project is created, add a new MFC class CServerSocket.

Step 4 − Select the CSocket as base class and cpck Finish.

Step 5 − Add more MFC class CReceivingSocket.

Step 6 − CRecevingSocket will receive incoming messages from cpent.

In CMFCServerApp, the header file includes the following files −

#include "ServerSocket.h"
#include "MFCServerView.h"

Step 7 − Add the following two class variables in CMFCServerApp class.

CServerSocket m_serverSocket;
CMFCServerView m_pServerView;

Step 8 − In CMFCServerApp::InitInstance() method, create the socket and specify the port and then call the Listen method as shown below.

m_serverSocket.Create(6666);
m_serverSocket.Listen();

Step 9 − Include the following header file in CMFCServerView header file.

#include "MFCServerDoc.h"

Step 10 − Override the OnAccept function from Socket class.

Step 11 − Select CServerSocket in class view and the highpghted icon in Properties window. Now, Add OnAccept. Here is the implementation of OnAccept function.

void CServerSocket::OnAccept(int nErrorCode) {

   // TODO: Add your speciapzed code here and/or call the base class
   AfxMessageBox(L"Connection accepted");
   CSocket::OnAccept(nErrorCode);
}

Step 12 − Add OnReceive() function.

void CServerSocket::OnReceive(int nErrorCode) { 
   
   // TODO: Add your speciapzed code here and/or call the base class
   AfxMessageBox(L"Data Received");
   CSocket::OnReceive(nErrorCode);
}

Step 13 − Add OnReceive() function in CReceivingSocket class.

Right-cpck on the CMFCServerView class in solution explorer and select Add → AddFunction.

Step 14 − Enter the above mentioned information and cpck finish.

Step 15 − Add the following CStringArray variable in CMFCServerView header file.

CStringArray m_msgArray;

Step 16 − Here is the implementation of AddMsg() function.

void CMFCServerView::AddMsg(CString message) {

   m_msgArray.Add(message);
   Invapdate();
}

Step 17 − Update the constructor as shown in the following code.

CMFCServerView::CMFCServerView() {

   ((CMFCServerApp*)AfxGetApp()) -> m_pServerView = this;
}

Step 18 − Here is the implementation of OnDraw() function, which display messages.

void CMFCServerView::OnDraw(CDC* pDC) {

   int y = 100;
   for (int i = 0; m_msgArray.GetSize(); i++) {
   
      pDC->TextOut(100, y, m_msgArray.GetAt(i));
      y += 50;
   }
   CMFCServerDoc* pDoc = GetDocument();
   ASSERT_VALID(pDoc);
   if (!pDoc)
      return;

   // TODO: add draw code for native data here
}

Step 19 − The server side is now complete. It will receive message from the cpent.

Create Cpent Side Apppcation

Step 1 − Let us create a new MFC dialog based apppcation for cpent side apppcation.

Step 2 − On Advanced Features tab, check the Windows sockets option as shown above.

Step 3 − Once the project is created, design your dialog box as shown in the following snapshot.

Step 4 − Add event handlers for Connect and Send buttons.

Step 5 − Add value variables for all the three edit controls. For port edit control, select the variable type UINT.

Step 6 − Add MFC class for connecting and sending messages.

Step 7 − Include the header file of CCpentSocket class in the header file CMFCCpentDemoApp class and add the class variable. Similarly, add the class variable in CMFCCpentDemoDlg header file as well.

CCpentSocket m_cpentSocket;

Step 8 − Here is the implementation of Connect button event handler.

void CMFCCpentDemoDlg::OnBnCpckedButtonConnect() {

   // TODO: Add your control notification handler code here
   UpdateData(TRUE);
   m_cpentSocket.Create();
   if (m_cpentSocket.Connect(m_ipAddress, m_port)) {
      AfxMessageBox(L"Connection Successfull");
   }else {
      AfxMessageBox(L"Connection Failed");
   }
   DWORD error = GetLastError();
}

Step 9 − Here is the implementation of Send button event handler.

void CMFCCpentDemoDlg::OnBnCpckedButtonSend() {

   // TODO: Add your control notification handler code here
   UpdateData(TRUE);
   if (m_cpentSocket.Send(m_message.GetBuffer(m_message.GetLength()), m_message.GetLength())) {
   
   }else {
      AfxMessageBox(L"Failed to send message");
   }
}

Step 10 − First run the Server apppcation and then the cpent apppcation. Enter the local host ip and port and cpck Connect.

Step 11 − You will now see the message on Server side as shown in the following snapshot.