Resource Cleanup and Lambda Expressions

03 November 20091 min read

A neat way of always cleaning up resources is to use Lambdas as data.

Take the following.

Source

    internal interface ITryCatchReport
    {
        void Try(Action<IServer> action);
    }

    internal class TryCatchReport : ITryCatchReport
    {
        public TryCatchReport(IServer server)
        {
            _server = server;
        }

        public void Try(Action<IServer> action)
        {
            try
            {
                action(_server);
            }
            catch (Exception e)
            {
                Trace.WriteLine(e.Message);
                // Clean up resources
                // Report errors
            }
        }

        private IServer _server;
    }

Usage

TryCatchReport safeInvoker = new TryCatchReport(_data.Server);
safeInvoker.Try(x =>
{
 x.MakeInterfaceCall();
});

We are now guaranteed that in the case of an exception the resources will get cleaned up.

Usage with code blocks

If you wish to execute many statements in the action look at this sample.

 private List<WFActionDefinition> GetActionDefinitions()
{
    if (_actionDefinitions == null)
    {
        safeInvoker.Try(x =>
            {
                x.Do1();
                x.DoSomething();
                OtherFunc();
            });
    }

    return _actionDefinitions;
}