//当Item展开时预先对其子项目进行填充，注意是子项目，之所以这样做是因为，子项目中如果含有其他项目，将会在图标上显示三角形符号，表示含有子目录
protected override void OnExpanded(RoutedEventArgs e)
{
base.OnExpanded(e);
foreach (object obj in this.Items)
{
DirectoryTreeViewItem item = obj as DirectoryTreeViewItem;
item.Populate();
}
}
public void RefreshTree()
{
this.BeginInit(); //执行后，TreeView控件会暂停进行显示的更新，不这么做会导致树的创建速度变慢
this.Items.Clear();
DriveInfo[] drives = DriveInfo.GetDrives();
foreach (DriveInfo drive in drives)
{
char chDrive = drive.Name.ToUpper()[0];
DirectoryTreeViewItem item = new DirectoryTreeViewItem(drive.RootDirectory);
//如果是只读的就显示卷标，否则就显示驱动器类型
if (chDrive != 'A' && chDrive != 'B' && drive.IsReady && drive.VolumeLabel.Length > 0)
{
item.Text = string.Format("{0} ({1})", drive.VolumeLabel, drive.Name);
}
else
{
item.Text = string.Format("{0} ({1})", drive.DriveType, drive.Name);
}
if (chDrive == 'A' || chDrive == 'B') //软盘驱动器
{
//item.SelectedImage = item.UnselectedImage = new BitmapImage(new Uri("pack://application:,,/Images/floppy_disk.png"));
item.SelectedImage = item.UnselectedImage = new BitmapImage(new Uri("pack://application:,,,/ManuallyPopulateTreeView;component/Images/floppy_disk.png"));
}
else if (drive.DriveType == DriveType.CDRom)
{
//item.SelectedImage = item.UnselectedImage = new BitmapImage(new Uri("pack://application:,,/Images/cd_drive.png"));
item.SelectedImage = item.UnselectedImage = new BitmapImage(new Uri("pack://application:,,,/ManuallyPopulateTreeView;component/Images/cd_drive.png"));
}
else
{
//item.SelectedImage = item.UnselectedImage = new BitmapImage(new Uri("pack://application:,,/Images/drive.png"));
item.SelectedImage = item.UnselectedImage = new BitmapImage(new Uri("pack://application:,,,/ManuallyPopulateTreeView;component/Images/drive.png"));
}
this.Items.Add(item);
if (chDrive != 'A' && chDrive != 'B' && drive.IsReady)
{
item.Populate();
}
}
this.EndInit();
}