HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\comdlg32\PlacesBar
OPENFILENAME ofn = {0};
ofn.lStructSize = sizeof(OPENFILENAME); // 必須 = 88 (WINVER>=0x0500)
ofn.Flags = OFN_EXPLORER | OFN_ENABLEHOOK; // 探索模式
// ... 其他字段
GetSaveFileName(&ofn);
關鍵:`lStructSize` 必須正確 (88 字節),且指定 `OFN_EXPLORER` 風格,PlacesBar 才生效。