Question

If a class has a property which contains unmanaged resources. How to make sure no memory leak when using the class

Class A
{
         B {get; set;}
}

B contains unmanaged resources.

Answer 1

Implement IDisposable and clean up your unmanaged resources by calling Dispose(), preferably placing the call to Dispose in a finally statement so you clean up resources even in the case of an exception.

C# has a using keyword that you can employ to make sure that the Dispose method is called, even if an exception is thrown.

EDIT: Incorporated call to GC.SuppressFinalize and finalizer implementation per Ran’s answer

class A : IDisposable
{
    private bool _disposed;

    ~A()
    {
        this.Dispose(false);
    }

    public void Dispose()
    {
        this.Dispose(true);
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
        if (!_disposed)
        {
            if (disposing)
            {
                // dispose managed resources
            }

            // clean up unmanaged resources

            _disposed = true;
        }
    }
}

class Program
{
    static void Main(string[] args)
    {
        using (var someInstance = new A())
        {
            // do some things with the class.
            // once the using block completes, Dispose
            // someInstance.Dispose() will automatically
            // be called
        }
    }
}