They’re also handy for refactoring switch statements. Take the following (albeit simple) example: public void Move(int distance, Direction direction) { switch (direction) { case Direction.Up : Position.Y += distance; break; case Direction.Down: Position.Y -= distance; break; case Direction.Left: Position.X -= distance; break; case Direction.Right: Position.X += distance; break; } } With an Action delegate, you … Read more
Eric Lippert recently wrote a series of blog posts about why yield is not allowed in some cases. Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 EDIT2: Part 7 (this one was posted later and specifically addresses this question) You will probably find the answer there… EDIT1: this is explained in … Read more
Because Invoke/BeginInvoke accepts Delegate (rather than a typed delegate), you need to tell the compiler what type of delegate to create ; MethodInvoker (2.0) or Action (3.5) are common choices (note they have the same signature); like so: control.Invoke((MethodInvoker) delegate {this.Text = “Hi”;}); If you need to pass in parameters, then “captured variables” are the … Read more
Short answer : no. Longer answer that may not be relevant: If you assign the lambda to a delegate type (such as Func or Action) you’ll get an anonymous delegate. If you assign the lambda to an Expression type, you’ll get an expression tree instead of a anonymous delegate. The expression tree can then be … Read more
Action myDelegate = delegate(){Console.WriteLine(“I did it!”);}; MyEvent += myDelegate; // …. later MyEvent -= myDelegate; Just keep a reference to the delegate around.
The compiler declares the variable in a way that makes it highly prone to an error that is often difficult to find and debug, while producing no perceivable benefits. Your criticism is entirely justified. I discuss this problem in detail here: Closing over the loop variable considered harmful Is there something you can do with … Read more