MSDN Documentation

Windows Programming Examples

Explore a collection of code examples to help you build powerful Windows applications.

• Creating a Basic Window

  Learn the fundamental steps to create a simple window using Win32 API, including message loop handling.

  #include <windows.h>
  
  LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
      switch (message) {
          case WM_DESTROY:
              PostQuitMessage(0);
              break;
          default:
              return DefWindowProc(hWnd, message, wParam, lParam);
      }
      return 0;
  }
  
  int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
      WNDCLASSEX wc = {0};
      wc.cbSize = sizeof(WNDCLASSEX);
      wc.lpfnWndProc = WndProc;
      wc.hInstance = hInstance;
      wc.lpszClassName = L"MyWindowClass";
  
      RegisterClassEx(&wc);
  
      HWND hWnd = CreateWindowEx(
          0,
          L"MyWindowClass",
          L"My First Window",
          WS_OVERLAPPEDWINDOW,
          CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
          NULL, NULL, hInstance, NULL
      );
  
      ShowWindow(hWnd, nCmdShow);
      UpdateWindow(hWnd);
  
      MSG msg = {0};
      while (GetMessage(&msg, NULL, 0, 0)) {
          TranslateMessage(&msg);
          DispatchMessage(&msg);
      }
  
      return msg.wParam;
  }

  Win32 API Beginner GUI

• Handling User Input with Mouse Events

  Demonstrates how to capture and respond to mouse clicks and movements within your window.

  // ... (previous code for window creation) ...
  
  LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
      switch (message) {
          case WM_LBUTTONDOWN: {
              int xPos = LOWORD(lParam);
              int yPos = HIWORD(lParam);
              MessageBox(hWnd, L"Left mouse button clicked!", L"Mouse Event", MB_OK);
              break;
          }
          case WM_MOUSEMOVE: {
              // You can track mouse movement here if needed
              break;
          }
          case WM_DESTROY:
              PostQuitMessage(0);
              break;
          default:
              return DefWindowProc(hWnd, message, wParam, lParam);
      }
      return 0;
  }
  
  // ... (rest of WinMain function) ...

  Win32 API Events Mouse

• Working with Standard Controls: Button and Edit Box

  Shows how to create and manage common Windows controls like buttons and editable text fields.

  // In WinMain, after CreateWindowEx:
  
  // Create a Button
  HWND hButton = CreateWindowEx(
      0, L"BUTTON", L"Click Me",
      WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON,
      10, 10, 100, 30,
      hWnd, (HMENU)1, hInstance, NULL
  );
  
  // Create an Edit Box
  HWND hEdit = CreateWindowEx(
      WS_EX_CLIENTEDGE, L"EDIT", L"",
      WS_TABSTOP | WS_VISIBLE | WS_CHILD | ES_AUTOHSCROLL,
      10, 50, 200, 30,
      hWnd, (HMENU)2, hInstance, NULL
  );
  
  // In WndProc, add a handler for button clicks:
  case WM_COMMAND:
      if (LOWORD(wParam) == 1) { // ID of the button
          MessageBox(hWnd, L"Button clicked!", L"Control Event", MB_OK);
      }
      break;
  
  // ...

  Win32 API Controls GUI Elements

• Asynchronous File I/O with Overlapped I/O

  An introduction to performing file operations asynchronously using the Windows API, preventing UI freezes.

  #include <windows.h>
  #include <iostream>
  
  // ... (Window setup and message loop) ...
  
  void PerformAsyncRead(HWND hWnd) {
      HANDLE hFile = CreateFile(
          L"mydata.txt", GENERIC_READ, FILE_SHARE_READ, NULL,
          OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL
      );
  
      if (hFile == INVALID_HANDLE_VALUE) {
          // Handle error
          return;
      }
  
      OVERLAPPED ol = {0};
      char buffer[256];
      DWORD bytesRead;
  
      // Associate the file handle with the window for completion notifications
      SetLastError(0); // Clear last error
      if (!AttachConsole(ATTACH_PARENT_PROCESS) && GetLastError() != ERROR_INVALID_HANDLE) {
           // You might want to redirect output to a debug console or log file
      }
      std::cout << "Attempting async read..." << std::endl;
  
  
      if (!ReadFile(hFile, buffer, sizeof(buffer) - 1, &bytesRead, &ol)) {
          DWORD error = GetLastError();
          if (error != ERROR_IO_PENDING) {
              // Handle other errors
              CloseHandle(hFile);
              return;
          }
          // IO is pending, GetOverlappedResult will be used later
          std::cout << "IO Pending." << std::endl;
      } else {
          // IO completed synchronously
          buffer[bytesRead] = '\0';
          std::cout << "Sync read complete: " << buffer << std::endl;
          CloseHandle(hFile);
      }
      // Note: You would typically handle the completion of pending IO
      // via WM_SOCKET message or GetOverlappedResult in a separate thread.
      // This example is simplified.
  }
  
  // In your WndProc, you might add a handler to trigger this:
  case WM_KEYDOWN:
      if (wParam == VK_F5) { // Press F5 to trigger async read
          PerformAsyncRead(hWnd);
      }
      break;
  
  // ...

  File I/O Asynchronous Advanced

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