title: How to select all items in a ListBox really fast?
body: <p>I have an ownerdrawn ListBox on a form (Windows Forms) binding to a datasource (BindingList).
  I need to provide an option to select all items (up to 500000) really fast.</p>
  
  <p>This is what I am currently doing:</p>
  
  <pre><code>for (int i = 0; i &lt; listBox.Items.Count; i++)
      listBox.SetSelected(i, true);
  </code></pre>
  
  <p>This is incredibly slow and not acceptable. Does anybody know a better solution?</p>