private void Form1_Load(object sender, System.EventArgs e)
{
    // Displays all physical drives
    // To avoid duplicate loading, use AutoInitialLoad = False in
    // property page
    axSftDirectory1.ControlStyle = SftDirectoryStyleConstants.styleSftDirectoryComboBoxDetailList;
    axSftDirectory1.TopMostFolderSpecial = SftDirectorySpecialFolderConstants.specialSftDirectoryMyComputer;
    axSftDirectory1.Headers.Style = SftDirectoryHeadersStyleConstants.headersSftDirectoryButton;
    axSftDirectory1.get_Column(SftDirectoryContentsConstants.contentsSftDirectoryName).HeaderText = "Drives";
}

private void axSftDirectory1_Filtering(object sender, AxSftDirectoryLib25._ISftDirectoryEvents_FilteringEvent e)
{
    // This filters out folders such as "Shared Documents", "Control Panel", which
    // are part of "My Computer"
    if (e.folder.Type >= SftDirectoryFolderTypeConstants.typeSftDirectory_Computer_Drive35 && 
            e.folder.Type <= SftDirectoryFolderTypeConstants.typeSftDirectory_Computer_Other)
        ;// OK, add this to the control contents
    else
        e.removeFolder = true; // don't add this to the control contents
}