Using a Bound Interface in F #
I'm trying to use a C # library in F #, so this would be a very specific case. I am using Servicestack with F #. Now I am trying to connect a class with an interface using the method
RegisterAutoWiredAs<T,'TAs>()
signature. Here "T has a limitation that it must implement" TA ". It works fine in C # code.
But F # has a limitation in using the interface.
let f:IFoo = Foo() // will give type error
let fi:IFoo - Foo() :> IFoo // will work
Here Foo has implemented IFoo. So this part is different from the C # equivalent. Now type error appears above the signature, if I like it
container.RegisterAutoWiredAs<Foo,IFoo>()
And now you need to do casting when setting the parameter.
Here is a line from the original project I am trying to run. Everything in this code works differently than this part, and also, unfortunately, other equivalent methods fail as well.
And here is the error I am getting in this project
This expression was expected to be of type 'MemoryChatHistory', but there is type 'IChatHistory' here
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F # does not support implicit interface implementations.
I think you can get around this in this case by making IChatHistory an abstract class rather than an interface (using an attribute [<AbstractClass>]
).
EDIT:
No, I had the opportunity to play with him today. I think it is not possible to directly call this method with these type parameters from F #. See this question
How to convert parameter constraint of type `T: U` from C # to F #?
for a more detailed discussion.
You might be able to get around this by using reflection to call the method.
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