I have a simple WPF program that just has a single button with no event handling logic. I then use the UIAutomation framework to click that button many times in a row. Finally, I look at the memory used by the WPF program and it seems to grow and grow.
Anyone know why this is the case and how I can prevent this from happening?
Here is the simple WPF program (nothing in the code behind):
<Window x:Class="SimpleApplication.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Simple Application"
AutomationProperties.AutomationId="Simple Application"
Height="350" Width="525">
<Grid>
<Button AutomationProperties.AutomationId="button" Height="50" Width="100">Click Me</Button>
</Grid>
</Window>
Here is the UIAutomation test program:
class Program
{
static void Main(string[] args)
{
string appPath = @"......SimpleApplicationinDebugSimpleApplication.exe";
string winAutoId = "Simple Application";
string buttonAutoId = "button";
using (Process process = Process.Start(new ProcessStartInfo(appPath)))
{
Thread.Sleep(TimeSpan.FromSeconds(1));
AutomationElement winElement = AutomationElement.RootElement.FindFirst(TreeScope.Children, new PropertyCondition(AutomationElement.AutomationIdProperty, winAutoId));
for (int i = 0; i < 1001; i++)
{
AutomationElement buttonElement = winElement.FindFirst(TreeScope.Descendants, new PropertyCondition(AutomationElement.AutomationIdProperty, buttonAutoId));
InvokePattern invokePattern = (InvokePattern)buttonElement.GetCurrentPattern(InvokePattern.Pattern);
invokePattern.Invoke();
process.Refresh();
long totalMemory = process.WorkingSet64 + process.PagedMemorySize64;
if (i % 100 == 0)
{
Console.WriteLine("Memory = {0} MB", ((double)totalMemory) / (1024 * 1024));
}
}
WindowPattern windowPattern = (WindowPattern)winElement.GetCurrentPattern(WindowPattern.Pattern);
windowPattern.Close();
}
Console.WriteLine();
Console.WriteLine("Press Enter to Continue...");
Console.ReadLine();
}
}
Here are the results from the program on my machine:
Memory = 38.20703125 MB
Memory = 42.9296875 MB
Memory = 45.00390625 MB
Memory = 47.04296875 MB
Memory = 51.9296875 MB
Memory = 52.2890625 MB
Memory = 52.41015625 MB
Memory = 55.70703125 MB
Memory = 55.70703125 MB
Memory = 57.21484375 MB
Memory = 59.09375 MB
Looking at it with the .NET Memory Profiler, the new objects that are appearing in the WPF application are from the System.Threading namespace. When I run the WPF program by itself and click the button with the mouse these objects do no appear.
UPDATE:
I tried doing a similar test using Visual Studio's CodedUI, and the same 8 objects appeared to leak in that situation as well. The objects that appear to leak are:
System.Threading.CancellationTokenSource
System.Threading.TimerQueueTimer
System.Threading.SparselyPopulatedArray<CancellationCallbackInfo>[]
System.Threading.Timer
System.Threading.TimerHolder
System.Threading.SparselyPopulatedArray<CancellationCallbackInfo>
System.Threading.SparselyPopulatedArrayFragment<CancellationCallbackInfo>
System.Threading.CancellationCallbackInfo[]
I have also submitted a bug to Microsoft:
http://connect.microsoft.com/VisualStudio/feedback/details/801209/uiautomation-memory-issue
See Question&Answers more detail:
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