Can named arguments be used with the params modifier?
.net, c#
Solution
The following code compiles without problems:
void Main()
{
Invoke(method: () => {}, args: new object[] {});
}
public object Invoke(Action method, params object[] args)
{
return null;
}
I had to change the type of the first parameter from `Delegate` to `Action` to make it compile, because `() => {}` can't be converted to `Delegate`.
Alternatively, the following does also compile:
void Main()
{
Action method = () => {};
Invoke(method: method, args: new object[] {});
}
public object Invoke(Delegate method, params object[] args)
{
return null;
}
My assumption is that you never got a compile error about the `args` parameter but about the `method` parameter saying "Cannot convert from 'lambda expression' to 'System.Delegate'". This problem is solved by either casting the lambda to an Action (`Invoke(method: (Action)(() => {}) ...`) or by defining a variable of type `Action` that is passed as parameter to the method (see above), because `Action` can implicitly be converted to `Delegate`.
Problem
I am trying to invoke `Invoke` on a `Dispatcher` using the following overload: ``` public object Invoke(Delegate method, params object[] args); ``` I want to use named arguments, but I can't seem to find the syntax for the argument with the params modifier. All of the following won't compile: ``` dispatcher.Invoke(method: () => { }, args: {}); dispatcher.Invoke(method: () => { }, args: new object[0]); dispatcher.Invoke(method: () => { }, args: null); dispatcher.Invoke(method: () => { }, args: new object[] {}); object[] foo = {}; dispatcher.Invoke(method: () => { }, args: foo); dispatcher.Invoke(method: () => { }, args: new[] {"Hello", "World!"}); ``` I found these two questions to which there seems to be no definite answers: Named parameters with params How to set named argument for string.Format? So my question is: can it be done or not? If yes, how? UDPATE Daniel Hilgarth's shows that yes `params` can be used with named parameters. I integrated his answer using this pattern: ``` Action method = () => { }; if (_dispatcher != null) _dispatcher.Invoke(method: method, args: null); else method(); ```