C#/F# interoperability

There are helper classes included in WebSharper for most common conversions between FSharp.Core and standard .NET types. These conversions work both on server and client side.

Create F# values from standard .NET counterparts

The WebSharper.FSharpConvert static class contains static members to create values used commonly in F#.

• FSharpConvert.Fun overloads create curried F# functions for 1-8 arguments from System.Action and System.Func delegate values.
• FSharpConvert.Option overloads create an FSharpOption<T> value from a value of a .NET reference type or Nullable value type. (To create a 1)
• FSharpConvert.List overloads create an FSharpList.
• FSharpConvert.Async overloads create an FSharpAsync<TResult> from a Task or Task<TResult>.
• FSharpConvert.Ref overloads create an FSharpRef object with specified initial value or default value for a type.
• Option.None and F# unit values can be just null.

Consume F# values from C#

Everything works as in .NET, there are no extra helpers provided by WebSharper.

• To call an FSharpFunc function, use its Invoke method. When calling curried F# functions, you have to chain calling Invoke to pass all arguments separately.
• Create F# union values using the .New... static method in the union type (or property for a union case with no fields).
• Create F# record values by using its constructor.
• Separate union cases by using the Is... methods, or the Tag property. Whenever a union has null as possible value, these methods are static.
• For the FSharpOption type, you can use x?.Value) to get the value or null.