Question

I am learning lambda expression and delegates.While i try to execute the following ,I am getting error at the line which is marked bold line. (Error : Operator += cannot be applied to operands of type Test.MessageDelegate and lambda expression ).Help me to handle lambda expression.

namespace Test
{
    public delegate void MessageDelegate(string title,object sender,EventArgs e);
    class Program
    {
        static event MessageDelegate logEvent;

        static void Main(string[] args)
        {
            logEvent = new MessageDelegate(OnLog);
            logEvent("title",Program.logEvent,EventArgs.Empty);

logEvent += (src, e) => { OnLog("Some",src, e); };

            Console.ReadKey(true);

        }

        static void OnLog(string title, object sender, EventArgs e)
        {
            if (logEvent != null)
            {
                Console.WriteLine("title={0}", title);
                Console.WriteLine("sender={0}", sender);
                Console.WriteLine("arguments={0}",e.GetType());
            }
        }
     }

 }

Answer 1

Since logEvent has MessageDelegate as its event handler, you d need the left hand of the lambda expression (src, e) to match the signature of MessageDelegate

Change to (str, src, e) => OnLog(str, src, e)

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