Question

I have problem with destructor after going out of scope(it is calling but after some time and need to make an action on form, for example change radio button), maybe there’s mistake in my code. Take a look:

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {

        public Form1()
        {
            InitializeComponent();
            EventLogger.Print += delegate(string output)
            { if (!textBox1.IsDisposed) this.Invoke(new MethodInvoker(() => textBox1.AppendText(output + Environment.NewLine)), null); };
        }

        private void button1_Click(object sender, EventArgs e)
        {
            TestClass test = new TestClass();
        }
    }
    public static class EventLogger
    {
        public delegate void EventHandler(string output);
        public static event EventHandler Print;
        public static void AddLog(String TextEvent)
        {
            Print(TextEvent);
        }
    }
    public class TestClass
    {
        public TestClass()
        {
            EventLogger.AddLog("TestClass()");
        }
        ~TestClass()
        {
            EventLogger.AddLog("~TestClass()");
        }
    }

}

Answer 1

Right, because this isn’t C++. The finalizer (not destructor as in C++) is not guaranteed to be called immediately after an object has left its declaring scope, it is called when the GC decides to swoop in and clean up after you.

May I ask why you are using a finalizer to begin with? Are you maintaining references to unmanaged resources which need to be deallocated as deterministically as possible (if so, read up on the IDisposable interface)? The use cases for C# finalizers are few and far between, it’s not common to implement them.