Back to Questions
2.3k
views1
comment
Mutable members in classes
f#classes

I'm making a class which contains a set of 12 floats for data storage, and it has to be mutable and accessible to WPF's binding mechanism.

Which brings us to the question - is there a better (shorthand!) way to do this:

type Affine() =
let mutable _a = 0.0
let mutable _b = 0.0
let mutable _c = 0.0
let mutable _d = 0.0
let mutable _e = 0.0
let mutable _f = 0.0
let mutable _g = 0.0
let mutable _h = 0.0
let mutable _i = 0.0
let mutable _j = 0.0
let mutable _k = 0.0
let mutable _l = 0.0
member s.a with get() = _a
and set x = _a <- x
member s.b with get() = _b
and set x = _b <- x
member s.c with get() = _c
and set x = _c <- x
member s.d with get() = _d
and set x = _d <- x
member s.e with get() = _e
and set x = _e <- x
member s.f with get() = _f
and set x = _f <- x
member s.g with get() = _g
and set x = _g <- x
member s.h with get() = _h
and set x = _h <- x
member s.i with get() = _i
and set x = _i <- x
member s.j with get() = _j
and set x = _j <- x
member s.k with get() = _k
and set x = _k <- x
member s.l with get() = _l
and set x = _l <- x

As you can see, it's rather ridiculous...

.

F# has no autoproperty syntax at the moment - I think it would be great.
My solution has been to declare these types of classes in a C# assembly, and ref. the DLL from F#. (I've been doing all WPF work from C# for designer support and writing the logic in F#.)

A record has auto-properties, so you can do this:

1
2
3

  type FloatsType = { _a : float, _b : float ... }
  let MyFloats = { _a = 0, ... }

Then in the binding, bind to "MyFloats._a", "MyFloats._b", etc.

Another solution would be to expose a single array, and just use the binding indexing syntax to bind to various sub-elements of the array, such as "MyFloats[0], MyFloats[1]", etc.

By on 8/5/2010 7:05 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