F# dll in F# script

Question

I have a C# dll that I need to reference in F#. I can do this fine in a .fs file, but I can't seem to get it to work in an F# script (.fsx) It is strange because in my script, I have no problem referencing F# dlls. I thought C# dlls and F# dlls were essentially the same.

EDIT:

I have two dlls (1) csharp.dll and (2) fsharp.dll built with csharp and fsharp respectively. I reference them with:

#r "bin\Debug\csharp.dll"
#r "bin\Debug\fsharp.dll"

which the compiler recognizes. The line where this occurs looks like this:

let new_object = new fsharp.type(Observable<csharp.type>)

Where I'm creating an object defined in fsharp.dll which takes an observer of a type defined in csharp.dll. When I try to run it in FSharp interactive, I get the following error:

error FS0074: The type referenced through 'csharp.type' is defined in an assembly that is not referenced. You must add a reference to assembly 'csharp'.

The thing that doesn't make sense is that csharp.type had been used successfully in a previous line. But when we introduce the csharp.type with an fsharp.type, I get an error all of a sudden saying the csharp type is missing an assembly reference, even though the problem seems to be with the fsharp.type.

Could you add a sample of script you are using and the error? Are you using #r directive to refer C# dll from the script? — Petr
What if you refer the full path of csharp.dll in the script. Will it give you the same error? — Petr
If I refer the full path of the csharp.dll, it actually tells me that the path doesn't exist, so I have to do it this way. — user3685285
note that the paths are .NET strings and you might have hit an escape sequence somewhere, so better use something like #r @"bin\Debug\csharp.dll" — scrwtp

Petr Petr · Accepted Answer · 2015-03-30T17:34:09

It seems you'll need also refer in the script System.Reactive.dll or wherever the class Observable<T> is defined

F# dll in F# script

2 Answers