F # MVVM event using WPF
I've been working with Event MVVM for a couple of weeks (first time using the design pattern in F #), and I love the idea of separating the view and model, and a "functional" controller. But when viewing the book in WPF it seems to me that it would be easier if I could dispatch events directly. Also in some situations I need to keep control of the code.
More specific:
- How to close window defined as usercontrol in XAML file
- There seems to be less need for buttons (triggering boolean states that hold state), with a more automated feel as a result if I could address events directly
Does anyone share this experience or am I still missing something? Is it advisable to go back to FsXaml or polyglot MVVM?
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It turns out that the code is actually very extensible. Based on demos I managed to turn the textbox into a numeric one. The code that does this is very simple, but I wanted to define a custom event accessory. What can be done:
Extend UserControl.xaml header with
xmlns:fsxaml="http://github.com/fsprojects/FsXaml"
fsxaml:ViewController.Custom="{x:Type views:CompositionUserControl}"
And replace the original code in UserControl.xaml.fs:
namespace Space.Views
open FsXaml
type UserView = XAML<"View/UserControl.xaml", true>
type CompositionUserControl () =
member __.ViewModel = Space.ViewModels.UserControlViewModel(Space.Models.Handling.proces)
from
namespace Space.Views
open FsXaml
open System
type UserView = XAML<"View/UserControl.xaml", true>
type CompositionUserControl () =
inherit UserControlViewController<UserView>()
let numeric (txt : string) =
try txt |> int with
| :? System.FormatException -> 0
| _ -> 1
override this.OnLoaded view =
view.Box.PreviewTextInput.Add(fun e -> if numeric e.Text = 0 then e.Handled <- true)
member __.ViewModel = Space.ViewModels.UserControlViewModel(Space.Models.Handling.proces)
EDIT
Looking back on this post, here's my progress regarding my initial questions:
How to close window defined as usercontrol in XAML file
Using the attached property DialogCloser .
There seems to be less need for buttons (triggering booleans that hold state), with a more automated feeling as a result if I could directly access events
The key point here is to learn:
- How to truly separate the view (model) from the model
- How to use XAML to use its full power.
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