Hi All!

First post here and I am certainly a QT newbie.

In my quest to learn the QT5 API & Widgets, I thought I would make a simple file explorer to allow a user to navigate a directory structure. I was pleasantly amazed at how quickly I could get this working in QT with the following code:

Qt Code: 
  1. void MainWindow::initTreeView()
  2. {
  3.     dirModel = new QFileSystemModel(this);
  4.     dirModel->setRootPath("");
  5.     dirModel->setFilter(QDir::AllDirs | QDir::NoDotAndDotDot);
  6.     ui->treeView->setModel(dirModel);
  7. }
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This works great at first, however as I navigate the ui->treeView I observed the following:

* Expanding a node with a large number of subdirectories (say over 10,000) causes the UI to become unresponsive for ~8-10 seconds. On my system (Windows 7), for instance C:\Windows\winsxs can easily have 10k+ subdirectories. According to the official QT documentation:

Unlike QDirModel(obsolete), QFileSystemModel uses a separate thread to populate itself so it will not cause the main thread to hang as the file system is being queried. Calls to rowCount() will return 0 until the model populates a directory.
* After expanding a large directory/node then collapsing this node as noted above, expanding other nodes (even nodes with only a few directories) becomes sluggish with a 2-3 second delay before the UI becomes responsive again.

I've also noticed that Windows Explorer can expand and navigate these structures instantly (with no detectable delay) so I'm most likely not doing something right here. Am I missing some optimization setting I should be turning on or am I expecting too much from QFileSystemModel?

Thanks in advance for any help!

- Zep