DlgDirListComboBox

[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Ansi)]
public static extern int DlgDirListComboBoxA(IntPtr hDlg,
   [MarshalAs(UnmanagedType.LPStr)] StringBuilder lpPathSpec,
   int nIDComboBox,
   int nIDStaticPath,
   uint uFiletype
);

Microsoft documentation: Link