Question

When I write in my code

Action(() => someCombobox.Text = "x" )

I get this error:

Delegate ‘System.Action<object>‘ does not take 0 arguments

Why?

This question is related to this one. I just want to understand why this error occurs.

Answer 1

If you wish to create a System.Action delegate which has no parameters and does not return a value, simply change your code to this, removing the new Action([body]):

Action newAction = () => someCombobox.Text = "x";

This is because the lambda expression will return a new parameterless System.Action delegate for you. EDIT: as noted by Aliostad, () => someCombobox.Text = "x" will return either a lambda expression or an Action, depending on the type of the variable you are assigning it to.

EDIT: as Darin says, if you wish it to accept an argument then you need to pass that in when creating the lambda expression.