Question

I have created a simple wpf C# with a single text box and DispatcherTimer that displays the result of a call to GC.GetTotalMemory(true) every second. The value returned increases steadily with each call, and task manager shows that the private working memory set increases also.
Is this really a memory leak, or just the appearance of one? In my real app that does a lot more within each tick the memory leakages appear significantly higher.
My code is as follows

xaml

<Window x:Class="TestWPFApplication.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <TextBox Name="memoryuseage"></TextBox>
    </Grid>
</Window>

xaml.cs

namespace TestWPFApplication
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        System.Windows.Threading.DispatcherTimer tmr;

        public Window1()
        {
            InitializeComponent();

            tmr = new System.Windows.Threading.DispatcherTimer();
            tmr.Interval = new System.TimeSpan(0, 0, 1);
            tmr.Tick += new EventHandler(StaticTick);
            tmr.Start();
        }

        void StaticTick(object o, EventArgs sender)
        {
            memoryuseage.Text = GC.GetTotalMemory(true).ToString();
        }
    }
}

Answer 1

Is this really a memory leak, or just the appearance of one?

Just the appearance. A steady increase is normal, it isn’t a leak until you can crash it by running it long enough. But that could take days with a small leak.

Your memory usage ought to level off, but only after a considerable time. You might be able to speed that up by using GC.Collect() here (every 10th tick or so).

For a serious diagnosis you will need a memory-profiler.

For example: http://en.wikipedia.org/wiki/CLR_Profiler