Is this slow WPF TextBlock performance expected?
- by Ben Schoepke
Hi,
I am doing some benchmarking to determine if I can use WPF for a new product. However, early performance results are disappointing. I made a quick app that uses data binding to display a bunch of random text inside of a list box every 100 ms and it was eating up ~15% CPU. So I made another quick app that skipped the data binding/data template scheme and does nothing but update 10 TextBlocks that are inside of a ListBox every 100 ms (the actual product wouldn't require 100 ms updates, more like 500 ms max, but this is a stress test). I'm still seeing ~10-15% CPU usage. Why is this so high? Is it because of all the garbage strings?
Here's the XAML:
<Grid>
<ListBox x:Name="numericsListBox">
<ListBox.Resources>
<Style TargetType="TextBlock">
<Setter Property="FontSize" Value="48"/>
<Setter Property="Width" Value="300"/>
</Style>
</ListBox.Resources>
<TextBlock/>
<TextBlock/>
<TextBlock/>
<TextBlock/>
<TextBlock/>
<TextBlock/>
<TextBlock/>
<TextBlock/>
<TextBlock/>
<TextBlock/>
</ListBox>
</Grid>
Here's the code behind:
public partial class Window1 : Window
{
private int _count = 0;
public Window1()
{
InitializeComponent();
}
private void OnLoad(object sender, RoutedEventArgs e)
{
var t = new DispatcherTimer(TimeSpan.FromSeconds(0.1), DispatcherPriority.Normal, UpdateNumerics, Dispatcher);
t.Start();
}
private void UpdateNumerics(object sender, EventArgs e)
{
++_count;
foreach (object textBlock in numericsListBox.Items)
{
var t = textBlock as TextBlock;
if (t != null)
t.Text = _count.ToString();
}
}
}
Any ideas for a better way to quickly render text?
My computer: XP SP3, 2.26 GHz Core 2 Duo, 4 GB RAM, Intel 4500 HD integrated graphics. And that is an order of magnitude beefier than the hardware I'd need to develop for in the real product.
