Keeping Values in the Registry

1. Start Microsoft Visual C++ or Visual Studio
2. Create a Dialog-Based application named Remember1
3. Delete the OK button and the TODO line
4. Change the Caption of the Cancel button to Close
5. Change the dialog's Border property to Resizing 
6. Generate the WM_DESTROY message of the dialog box
7. Implement its OnDestroy event as follows:
    

   void CRemember1Dlg::OnDestroy() { CDialog::OnDestroy(); // TODO: Add your message handler code here CRect rctPosition; HKEY hk; DWORD dwDisp; TCHAR dwData[40]; // Retrieve the position and size of the dialog box GetWindowRect(&rctPosition); // Check the HKEY_CURRENT_USER key and look // for the RemDlgPos node under // If you don't find it, then create it RegCreateKeyEx(HKEY_CURRENT_USER, "RemDlgPos", 0, NULL, REG_OPTION_NON_VOLATILE, KEY_WRITE, NULL, &hk, &dwDisp); // Retrieve the value of the x coordinate of the dialog box... sprintf(dwData, "%d", rctPosition.left); // ... and store it in a key named Left RegSetValueEx(hk, "Left", 0, REG_DWORD, (PBYTE)&dwData, sizeof(PDWORD)); // Retrieve the value of the y coordinate of the dialog box... sprintf(dwData, "%d", rctPosition.top); // ... and store it in a key named Top RegSetValueEx(hk, "Top", 0, REG_DWORD, (PBYTE)&dwData, sizeof(PDWORD)); // Retrieve the width of the dialog box... sprintf(dwData, "%d", rctPosition.Width()); // ... and store it in a key named Width RegSetValueEx(hk, "Width", 0, REG_DWORD, (PBYTE)&dwData, sizeof(PDWORD)); // Retrieve the height of the dialog box... sprintf(dwData, "%d", rctPosition.Height()); // ... and store it in a key named Height RegSetValueEx(hk, "Height", 0, REG_DWORD, (PBYTE)&dwData, sizeof(PDWORD)); // We have finished with the registry, // so liberate the resources we were using RegCloseKey(hk); }

8. Generate the WM_CREATE message of the dialog box
9. Implement its OnCreate event as follows:
    

   int CRemember1Dlg::OnCreate(LPCREATESTRUCT lpCreateStruct) { if (CDialog::OnCreate(lpCreateStruct) == -1) return -1; // TODO: Add your specialized creation code here // This variable will allow us to keep track of the KEY HKEY hk; // This variable will be used to hold the type of value DWORD dwType; // This variable will represent the size of the value DWORD dwLength; // These variables represent the position // and the size of the dialol box TCHAR strValueLeft[20], strValueTop[20], strValueWidth[20], strValueHeight[20]; // Check the HKEY_CURRENT_USER node and look for // the RemDlgPos node under it // If it exists, open it RegOpenKeyEx(HKEY_CURRENT_USER, "RemDlgPos", 0, KEY_QUERY_VALUE, &hk); // Retrieve the value of the Left key RegQueryValueEx(hk, "Left", NULL, NULL, (LPBYTE)strValueLeft, &dwLength); // Retrieve the value of the Top key RegQueryValueEx(hk, "Top", NULL, &dwType, (LPBYTE)strValueTop, &dwLength); // Retrieve the value of the Width key RegQueryValueEx(hk, "Width", NULL, &dwType, (LPBYTE)strValueWidth, &dwLength); // Retrieve the value of the Height key RegQueryValueEx(hk, "Height", NULL, &dwType, (LPBYTE)strValueHeight, &dwLength); // We have finished reading the registry, // so free the resources we were using RegCloseKey(hk); // Use the values retrieved from the retrieve to place the dialog box // where it was the previous time this->SetWindowPos(&wndTop, atoi(strValueLeft), atoi(strValueTop), atoi(strValueWidth), atoi(strValueHeight), SWP_SHOWWINDOW); return 0; }

10. Execute the application
11. Resize the move the dialog box around
12. Close the dialog box
13. Execute the application again and notice that it remembers where the dialog box was last positioned
14. Open the registry and examine the HKEY_CURRENT_USER node. Notice that it has a new node named RegDlgPos
15. Close the registry