c# : simulate memory leaks

Question

I would like to write the following code in c#. a) small console application that simulates memory leak. b) small console application that would invoke the above application and release it right away simulating managing memory leak problem..

In other words the (b) application would continuously call and release application (a) to simulate how the "rebellious" memory leak application is being contained with out addressing the root cause which is application (a).

Some sample code for application (a) and (b) would be very helpful.

Thanks

Answer 1

In a Console or Win app create a Panel object(panel1) and then add 1000 PictureBox having its Image property set then call panel1.Controls.Clear. All PictureBox controls are still in the memory and no way GC can collect them:

var panel1 = new Panel();
var image = Image.FromFile("image/heavy.png");
for(var i = 0; i < 1000;++i){
  panel1.Controls.Add(new PictureBox(){Image = image});
}
panel1.Controls.Clear(); // => Memory Leak!

The correct way of doing it would be

for (int i = panel1.Controls.Count-1; i >= 0; --i)
   panel1.Controls[i].Dispose();

Memory leaks in calling Controls.Clear()

Calling the Clear method does not remove control handles from memory. You must explicitly call the Dispose method to avoid memory leaks

Answer 2

The leaking application might look like:

public static void Main()
{
  var list = new List<byte[]>();
  while (true)
  {
    list.Add(new byte[1024]); // Change the size here.
    Thread.Sleep(100); // Change the wait time here.
  }
}

And the calling application might look like:

public static void Main()
{
  Process process = Process.Start("leaker.exe");
  process.Kill();
}

Take a look at the properties on the Process class. There are several that return how much memory the process is consuming. You may be able to use one of them to conditionally kill the process.