F# Silverlight 2 and Isolated Storage

I recently picked up a copy of the book Silverlight 2 Recipes and wanted to try out some of the recipes by building F# version of them.   One of the first recipes that caught my eye was recipe 2.6 which talks about working with IsolatedStorage.  One of the main issues I had with implementing this recipe in F# is the fact that the public methods for IsolatedStorageFile is different between .NET Framework 3.5 and for Silverlight 2.  Therefore, I was unable to call the CreateFile method of IsolatedStorageFile .  But thankfully, this problem was already resolved by Michael Giagnocavo in his blog on F# 1.9.6.2 and Silverlight 2.  All I had to do is goto Project->[ProjectName] Properties –> Build and enter the following flag in “Other flags:”

--cliroot "C:\Program Files\Microsoft Silverlight\2.0.31005.0"

After configuring the ––cliroot flag, the source file compiled without problems.  Here’s the F# implementation of recipe 2.6 from the book:

#light
namespace SilverLightFSharp

open System.IO
open System.IO.IsolatedStorage
open System.Windows
open System.Windows.Controls
open System.Windows.Media
open System.ServiceModel
open List

// Recipe 2-6 from Silverlight 2 Recipes book
// Persisting Data on the Client

type MyPage() = class
    inherit UserControl()
    
    let settings = IsolatedStorageSettings.ApplicationSettings
    let setting = "MySettings"
    let filename = "FormFields.data"
    let dataDirectory = "FormData"
    let filepath = System.IO.Path.Combine(dataDirectory, filename)
    
    //new () as this = {} then
    do
        let buildgrid color =
            let grid = new Grid(Background = new SolidColorBrush(color))
            let star = GridUnitType.Star
            
            // Add column definitions
            [0.06;0.455;0.485] 
            |> map (fun w -> new ColumnDefinition(Width=new GridLength(w,star)))
            |> iter grid.ColumnDefinitions.Add
            
            // Add row definitions
            [0.08;0.217;0.61;0.093]
            |> map (fun h -> new RowDefinition(Height=new GridLength(h,star)))
            |> iter grid.RowDefinitions.Add
            
            grid
            
        let grid =  buildgrid Colors.Gray
        
        let gridadd (ui:#UIElement) row col =
            grid.Children.Add(ui)
            Grid.SetRow(ui,row)
            Grid.SetColumn(ui,col)
            

        
        let sp = new StackPanel(HorizontalAlignment = HorizontalAlignment.Stretch,
                                Margin=new Thickness(8.0,8.0,10.0,8.0))
        
        
        new TextBlock(Text="Enter Setting Value",
                      TextWrapping=TextWrapping.Wrap,
                      Margin=new Thickness(4.0,4.0,4.0,4.0))
        |> sp.Children.Add
        
        let textdata = new TextBox(Height=126.0,
                                   Text="",
                                   TextWrapping=TextWrapping.Wrap,
                                   Margin=new Thickness(4.0,4.0,4.0,4.0))
        textdata |> sp.Children.Add

        gridadd sp 2 1
        
        
        // Build Form
        let buildform () =
            let brush = new LinearGradientBrush
                         (StartPoint = new Point(0.439999997615814,0.996999979019165),
                          EndPoint = new Point(0.560000002384186,0.00300000002607703))
                                                
            [((255uy,58uy,108uy,87uy),0.0);
             ((255uy,163uy,189uy,163uy),0.536);
             ((255uy,58uy,108uy,87uy),0.968999981880188)]
            |> map (fun (color,offset) -> new GradientStop(Color=(color |> Color.FromArgb), Offset=offset))
            |> iter brush.GradientStops.Add
            
            let form = new StackPanel(HorizontalAlignment = HorizontalAlignment.Stretch,
                                      VerticalAlignment = VerticalAlignment.Stretch,
                                      Margin = new Thickness(4.0,4.0,4.0,4.0))
            let border = new Border
                          (HorizontalAlignment = HorizontalAlignment.Stretch,
                           Margin = new Thickness(8.0,8.0,10.0,8.0),
                           VerticalAlignment = VerticalAlignment.Stretch,
                           CornerRadius = new CornerRadius(10.0,10.0,10.0,10.0),
                           Child=form,
                           Background=brush)
            gridadd border 2 2
            Grid.SetRowSpan(border,2)
            
            let createLabel label = new TextBlock(Text=label, 
                                                  TextWrapping=TextWrapping.Wrap,
                                                  Margin = new Thickness(2.0,4.0,2.0,0.0))
            let createTextbox () = new TextBox(TextWrapping=TextWrapping.Wrap,
                                               Margin = new Thickness(2.0,0.0,2.0,2.0))
                                               
                                                                                       
            let formelements = 
               ["First Name:";"Last Name:"; "Company:"; "Title:"]
               |> map (fun label -> (createLabel label, createTextbox ()))

            
            formelements |> iter (fun (label,tb) -> 
               form.Children.Add(label)
               form.Children.Add(tb))

            formelements
        
        
        let createbtn thickness row col content fn =
        
            let btn = new Button(HorizontalAlignment = HorizontalAlignment.Stretch,
                                 Margin=thickness,
                                 Content=content)
            btn.Click.Add(fn)
            btn.Click.Add(fun evt -> ())
            gridadd btn row col
         

        let form = buildform()
        let fields = form |> map (fun (label,tb) -> tb)
        
        // SaveFormData_Click
        createbtn (new Thickness(8.0)) 1 1 "Save Form Data"
        <| (fun evt -> 
                try
                    use store = IsolatedStorageFile.GetUserStoreForApplication()
                    store.CreateDirectory(dataDirectory)
                    use stream = store.CreateFile(filepath)
                    use writer = new StreamWriter(stream)
                    writer.AutoFlush <- true
                    let data = fields |> map (fun field -> field.Text + "|")  
                               |> fold_left (+) ""
                    data |> writer.WriteLine
                    textdata.Text <- "Data saved to : " + filepath + "\n" + data
                with 
                   | :? IsolatedStorageException as ex ->  textdata.Text <- "Error saving setting: " + ex.Message
                   | _ -> textdata.Text <- "Unable to open file... ")
        
        // ReadFormData_Click
        createbtn (new Thickness(8.0)) 1 2 "Load Form Data"
        <| (fun evt -> 
                try
                   use store = IsolatedStorageFile.GetUserStoreForApplication()
                   use file = new IsolatedStorageFileStream(filepath,FileMode.Open, store)
                   use reader = new StreamReader(file)
                   let storedvalues = reader.ReadToEnd();
                   let data = storedvalues.Split([|'|'|]) 
                              |> Array.to_seq |> Seq.take (List.length fields) 
                              |> Seq.to_list
                   zip fields data |> iter (fun (tb,data) -> tb.Text <- data)
                   // For checking...
                   textdata.Text <- storedvalues
                with
                   | :? IsolatedStorageException as ex ->  textdata.Text <- "Error saving setting: " + ex.Message
                   | _ -> textdata.Text <- "Unable to open file... ")
       
        // ButtonUpdateSetting - repurposed for diagnostics
        createbtn (new Thickness(4.0,4.0,14.0,4.0)) 3 1 "Update Setting"
        <| (fun evt -> 
               use store = IsolatedStorageFile.GetUserStoreForApplication()
               let dirs = store.GetDirectoryNames("*")
               let files = store.GetFileNames("*")
               let dirtext = "Directories = " + (dirs |> Array.to_list |> map (fun t -> "\n"+t)  |>fold_left (+) "")
               let filetext = "Filenames = " + (files |> Array.to_list |> map (fun t -> "\n"+t)  |>fold_left (+) "")
               textdata.Text <- dirtext + "\n" + filetext)
                
        base.Width <- 400.0
        base.Height <- 300.0
        base.Content <- grid
        
        // Loaded...
        try
            if settings.Keys.Count <> 0 then
               textdata.Text <- settings.[setting].ToString()
        with _  as ex -> textdata.Text <- "Error saving setting: " + ex.Message
        
end

type MyApp = class
    inherit Application
    
    new () as this = {} then
        this.Startup.Add(fun _ ->  this.RootVisual <- new MyPage())
        //base.Exit.Add( fun _ -> ()) //this.Application_Exit)
        //this.InitializeComponent()
end