Action<object, EventArgs> could not be cast to EventHandler?
.net, c#, casting, event-handling
Solution
Lambdas are implicitly convertible to delegate types with the right shape, but two same-shaped delegate types are not implicitly convertible to one another. Just make the local variable have type EventHandler instead.
EventHandler h = (o, ea) => { ... };
e += h;
...
e -= h;
(in case it helps:
Action<object, EventArgs> a = (o, ea) => { };
EventHandler e = a; // not allowed
EventHandler e2 = (o,ea) => a(o,ea); // ok
)
Problem
I was wiring up an event to use a lambda which needed to remove itself after triggering. I couldn't do it by inlining the lambda to the += event (no accessable variable to use to remove the event) so i set up an `Action<object, EventArgs>` variable and moved the lambda there. The main error was that it could not convert an `Action<object, EventArgs>` to an EventHandler. I thought lambda expressions were implicitly convertable to event handlers, why doesn't this work?