Back to Questions
2.5k
views4
comments
F# with Silverlight: Method not found: 'System.Array System.Array.CreateInstance(System.Type, Int32[], Int32[])'.
f#silverlight

Hi I'm trying to get some of the F# samples to work with Silverlight but I'm running in to a particular problem relating to the creation of an array. I get the following error when calling the below code from a class in a silverlight project

Method not found: 'System.Array System.Array.CreateInstance(System.Type, Int32[], Int32[])'.

(reduced code):

type cell =

{ x: int

y: int }

let dummy_cell =

{ x=0

y=0}

type grid =

{arr: cell[,]}

type TestClass() =

let empty =

{arr = Array2.create 0 0 dummy_cell;}

I can look in the object browser and can see that this method is not available, but I don't understand how the F# code is compiling given its pointing at the silverlight libraries. Any help or suggestions would be greatly appreciated.

Daniel

.

This issue is known to us; Array2.create won't work right now because it references the 'based' array creation methods (which Silverlight does not support). I think the workaround is to avoid calling Array2.create, and instead call the .Net Array.CreateInstance method

[link:msdn.microsoft.com]

and I think you can cast the result back to an F# 2-D array type.

By on 1/12/2009 3:40 PM ()

Hi Brian, thanks a lot, I thought that would be the right track so I can do this

let hold2 = System.Array.CreateInstance(typeof<cell>, [|0;0|]);;

but I can't get the type I need again e.g.

let hold3 = hold2 :> cell[,]

any suggestions?

many thanks daniel

By on 1/14/2009 6:05 AM ()
1
2
3
4

type cell = C 
let hold2 = System.Array.CreateInstance(typeof<cell>, [|1;1|])
let hold3 = hold2 :?> cell[,] 
hold3.[0,0] <- C

It's a downcast, not an upcast, so you need ":?>" rather than ":>".

By on 1/14/2009 8:17 AM ()

ha, easy, when you know. many thanks!

By on 1/15/2009 9:36 AM ()

    Topic tags

    IntelliFactory Offices Copyright (c) 2011-2012 IntelliFactory. All rights reserved.
    Home | Products | Consulting | Trainings | Blogs | Jobs | Contact Us | Terms of Use | Privacy Policy | Cookie Policy     		Built with WebSharper