An Original Idea

When User Experience doesn’t matter

anoriginalidea — Wed, 18 Nov 2009 23:26:35 +0000

I spend a great deal of time preaching the merits of user experience. Software design is about the end user, not about my preferences as a user of software.

I particularly subscribe to the ideas in Alan Cooper’s work “Face 3” and the book the “Inmates are Running the Asylum”. This involves researching one’s target market, creating personas typical of that market, then having those personas participate in realistic scenarios, which may or may not involve your software.

I think I’ve learnt the hard way, however, that sometimes designing the ideal user experience can be, frankly, a waste of time.

In a recent presentation, designer Joel Flom relates how designers sometimes create great designs which are gratefully received by the customer, who then proceed to take the design, consider it completely unworkable then place it in a box, never to be looked at again. So all time spent in design, documentation and analysis is of no benefit to anyone.

Although creating a “world” (via personas and scenarios) that accurately model a user experience, we need to be careful that we do not lose sight of two highly influential factors.

The first is ensuring that the personas we create truly do reflect the attitudes of our target market. It’s tempting to create a persona that is a user advocate, that loves our company and wants to form a relationship with it. This makes me feel warm inside but i don’t think it reflects every persons expectations. Most people want to do something quickly and easily. They’re not interested in taking us out to dinner. Creating an elaborate “UX” for these people can be a waste of time.

The second involves the other stakeholders in the software project. I’m talking about the analysts, developers, other designers, consultants and marketing that are expected to implement your ideas. They have opinions too and need to be heard. If they aren’t then they will either consciously or subconsciously sabotage or modify your grand plans beyond recognition.

Joel provides 3 thoughts that may help. Firstly, get a complete picture of the customer experience, not just an idealised one. Become a student of the business, not just your customer’s business, but your own. Understand what all the stakeholders want, particularly those responsible for implementing your solution. Give the customer what they really need, not just what’s “cool”. Having a more complete understanding of the problem will result in a truly effective solution.

Hosting Winforms in Firefox

anoriginalidea — Mon, 16 Nov 2009 01:42:39 +0000

I have a strange fascination with hybrids. Combining old and new technologies in bizarre and interesting ways. Why must developers make “the choice” between a web or native technology? It would be great to build applications that would increase or decrease in features depending on the platform they were run on.

Do you have a Winforms application that you’d like to host in a web browser? There’s an interesting technique you can use to do this enabled by .net Framework 3.5.

The .net framework provides the ability to create WPF web applications (commonly called XBAP). WPF has the ability, in turn, to host Winforms.

Security

It appears that in order to do this effectively, it’s necessary to deploy your XBAP application as a “Full Trust” application.

The code

To use this, create an XBAP project, then a page a “WinformHost” control on it. The XAML could look like this:

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Page1">

Then, create some code to instantiate your winform and show it on the Winform host:

Class Page1


    Private Sub Page1_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded 
        Dim loForm As New HelloWorldWinform 
        WinformHost.Child = WinformToUserControl.GetWrapper(loForm)      
        loForm.Show() 
    End Sub      
End Class

Here’s the subroutine:

Public NotInheritable Class WinformToUserControl


    Public Shared Function GetWrapper(ByVal form As System.Windows.Forms.Form) As System.Windows.Forms.Control       
        Dim loPanel As New System.Windows.Forms.Panel       
        loPanel.Dock = Forms.DockStyle.Fill       
        ShowFormInControl(loPanel, form)       
        Return loPanel       
    End Function
    Private Shared Sub ShowFormInControl(ByVal ctl As System.Windows.Forms.Control, ByVal frm As System.Windows.Forms.Form) 
        frm.TopLevel = False      
        frm.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None       
        frm.AutoScaleMode = Forms.AutoScaleMode.Dpi       
        ctl.Controls.Add(frm) 
        frm.Dock = Forms.DockStyle.Fill      
    End Sub      
End Class

Interesting bits and pieces

We found that in order for the items inside the control to scale properly, the AutoScaleMode property on the Winform must be set to Dpi instead of the default, which is Font. I have a feeling this is because Dpi is the mode preferred for WPF, but I am uncertain.

In the sample WinformToUserControl class I found it better to contain the Winform inside a panel rather than exposing the Winform directly. It seemed to make it more stable. Feel free to experiment with taking it off.

Gotchas

As of time of writing, Firefox on my Windows 7 64 bit machine steadfastly refuses to run xbap. It appears the “Windows Presentation Foundation” addin has not been automatically installed. I have no idea how to install it. There’ appears to be no information about how to do so. So if you have it, good for you. If you don’t….try re-installing the .net framework 3.51 (which didn’t work for me…)

I do know there was some controversy about this addin being temporarily blacklisted by Mozilla due to security concerns last month, but that’s all over now isn’t it?

Download

You can download a sample project here.

Enabling callto (Skype) in your application

anoriginalidea — Wed, 30 Sep 2009 08:26:06 +0000

You may have noticed that Skype seems to embed itself into Internet Explorer, Firefox and Chrome. It recognises contacts and phone numbers in the page and provides the ability to call them.

I believe people will expect this kind of functionality in conventional windows applications also. To assist with this I created a little class that will not only allow calls, but allows a check for the existence of a skype and give the ability to extract the calling applications icon.

Sample Project

The sample winforms project includes the CallTo class and a simple Winforms test form:

The form has a textbox and button. One load, the call button is enabled and give an image. The button makes the call.

Public Class Form1


    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load      
        Dim loCallTo As New CallTo       
        cmdCall.Image = loCallTo.Image       
        cmdCall.Enabled = loCallTo.Enabled       
    End Sub       
    Private Sub cmdCall_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdCall.Click       
        Dim loCallTo As New CallTo       
        loCallTo.DoCall(txtPhoneNumber.Text)       
    End Sub 
End Class

Heres the source of CallTo.vb:

Imports Microsoft.Win32 Imports System.Runtime Imports System.Runtime.InteropServices


''' 
      
''' This class allows for making callto calls       
''' 
       
Public Class CallTo 
    ''' 
      
    ''' Gets the image.       
    ''' 
       
    ''' The image.       
    Public ReadOnly Property Image() As Image       
        Get       
            If Not Enabled Then Return Nothing 
            Dim lsValue As String      
            With Registry.ClassesRoot.OpenSubKey("callto\DefaultIcon")       
                lsValue = .GetValue("")       
            End With 
            If lsValue.Contains(",") Then      
                Dim lsBits() As String = lsValue.Split(","c)       
                Dim lsFilename As String = lsBits(0).Trim(New Char() {""""c})       
                Dim liPosition As Integer = Val(lsBits(1))       
                Return moGetIconFromExeOrDll(lsFilename, liPosition)       
            Else       
                Return Nothing       
            End If 
        End Get      
    End Property       
    Private Declare Auto Function ExtractIcon Lib "shell32" ( _       
ByVal hInstance As IntPtr, ByVal lpszExeFileName As String, _       
ByVal nIconIndex As Integer) As IntPtr       
    Private Function moGetIconFromExeOrDll(ByVal filename As String, ByVal position As Integer) As Image       
        Dim hInstance As IntPtr = Marshal.GetHINSTANCE( _       
           System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0))       
        Dim hIcon As IntPtr = ExtractIcon(hInstance, filename, position)       
        Dim loBitmap As Bitmap = Bitmap.FromHicon(hIcon)       
        Dim loReturn As Image = loBitmap.GetThumbnailImage(16, 16, Nothing, Nothing) 
        loBitmap.Dispose()      
        Return loReturn 
    End Function 
    '''

      
    ''' Gets a value indicating whether this CallTo is enabled.       
    '''     ''' true if enabled; otherwise, false.       
    Public ReadOnly Property Enabled() As Boolean       
        Get       
            Try       
                Dim loReg As RegistryKey = Registry.ClassesRoot.OpenSubKey("callto", False)       
                loReg.Close()       
            Catch       
                Return False       
            End Try       
            Return True       
        End Get       
    End Property       
    '''        
    ''' Does the call.       
    ''' 
       
    ''' The destination.       
    Public Sub DoCall(ByVal destination As String) 
        If Not Enabled Then Throw New ApplicationException("Callto is not enabled")      
        Process.Start("callto://" & destination) 
    End Sub 
End Class

Download Sample

Using Sketchflow to create iPhone UX Prototypes

anoriginalidea — Mon, 21 Sep 2009 04:03:37 +0000

I’ve been using Expression Sketchflow for many things over the past few weeks for both prototyping Winforms, mobile, web and sometimes even Silverlight applications.

Once you give up on the idea of reusing your prototype it’s amazing what it can be used for.

I’ve found the creation of an iPhone usercontrol useful in prototyping. Simply add iPhone.xaml to your project and drop this onto your screens.

To create iPhone.xaml, create a blank usercontrol, then use the following xaml (remember to change MyProject to the name of your project):

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    xmlns:ps="clr-namespace:Microsoft.Expression.Prototyping.SketchControls;assembly=Microsoft.Expression.Prototyping.SketchControls"
    x:Class="MyProject.iPhone"
    d:DesignWidth="341" d:DesignHeight="685" Width="341" Height="685">

Sketchflow – “Duplicate” Bug

anoriginalidea — Wed, 26 Aug 2009 23:43:05 +0000

The Problem

At the moment I’m trialling Sketchflow for Expression Blend. There’s an annoying bug that happens when you use the “Duplicate” action on a node:

If you use this action, sooner or later you’ll end up with this error:

‘InitializeComponent’ is not a member of ‘xxxxxxxxxx.xxxxxxxxxxxxxx’

This can be very frustrating if you are trying to advocate Sketchflow as a prototyping tool for non wpf savvy analysts.

The Workaround

The simplest workaround is to delete the code-behind file. To do this, go to the project pane and choose “Delete”.

At first I tried hard to ensure that the xaml filenames and classnames were correct. This just causes a cascading comedy of errors.

Upgrading Sketchflow prototype projects to real code is a pipe-dream at the moment.

If you know of a better way of handling this situation (and fixing the errors) more quickly, feel free to comment. I just want get on with the prototyping.

Serialize and Deserialize objects as Xml using generic types in VB.Net

anoriginalidea — Mon, 10 Aug 2009 06:55:13 +0000

In his blog post Serialize and deserialize objects as xml using generic types in C# 2.0 , Paul Whitaker creates some ubiquitous functions for doing Xml Serialization with generics.

To serialize:

Dim lsXml As String = GenericXmlSerializer.SerializeObject(of MyObjectType)(myObject)

To deserialize:

Dim myObject As MyObjectType = GenericXmlSerializer.DeserializeObject(of MyObjectType)(lsXml)

Here’s the code

Imports System.Collections.Generic Imports System.Text Imports System.Xml Imports System.IO Imports System.Xml.Serialization


Class GenericXmlSerializer      
    ''' 
       
    ''' To convert a Byte Array of Unicode values (UTF-8 encoded) to a complete String.       
    ''' 
       
    ''' Unicode Byte Array to be converted to String       
    ''' String converted from Unicode Byte Array       
    Public Shared Function UTF8ByteArrayToString(ByVal characters As Byte()) As String 
        Dim encoding As New UTF8Encoding      
        Dim constructedString As String = encoding.GetString(characters)       
        Return constructedString 
    End Function 
    ''' 
      
    ''' Converts the String to UTF8 Byte array and is used in De serialization       
    ''' 
       
    '''        
    '''        
    Public Shared Function StringToUTF8ByteArray(ByVal pXmlString As String) As Byte() 
        Dim encoding As New UTF8Encoding()      
        Dim byteArray As Byte() = encoding.GetBytes(pXmlString)       
        Return byteArray       
    End Function 
    ''' 
      
    ''' Serialize an object into an XML string       
    ''' 
       
    '''        
    '''        
    '''        
    Public Shared Function SerializeObject(Of T)(ByVal obj As T) As String 
        Try      
            Dim xmlString As String = Nothing 
            Dim memoryStream As New MemoryStream()      
            Dim xs As New XmlSerializer(GetType(T))       
            Dim xmlTextWriter As New XmlTextWriter(memoryStream, Encoding.UTF8)       
            xs.Serialize(xmlTextWriter, obj)       
            memoryStream = CType(xmlTextWriter.BaseStream, MemoryStream)       
            xmlString = UTF8ByteArrayToString(memoryStream.ToArray())       
            memoryStream.Dispose() 
            Return xmlString      
        Catch 
            Return String.Empty      
        End Try       
    End Function 
    ''' 
      
    ''' Reconstruct an object from an XML string       
    ''' 
       
    '''        
    '''        
    Public Shared Function DeserializeObject(Of T)(ByVal xml As String) As T 
        Dim xs As New XmlSerializer(GetType(T))      
        Dim memoryStream As New MemoryStream(StringToUTF8ByteArray(xml))       
        Dim xmlTextWriter As New XmlTextWriter(memoryStream, Encoding.UTF8) 
        Dim theObject As T = CType(xs.Deserialize(memoryStream), T)      
        memoryStream.Dispose()       
        Return theObject 
    End Function 
End Class

Rather than be original, I converted most of his code verbatim and have found the functions useful.

I offer them to you warranty free, unadorned and hopefully useful.

Share this post :

Flick Scrolling in Winforms

anoriginalidea — Mon, 10 Aug 2009 00:12:16 +0000

In the article A Simple Scroll Controller for Winforms I mentioned that I was working on a FlickScrolling framework for Winforms.

I finished a version of this code a couple of months ago and it seems to work well.

The code never went into production because I think that Windows 7 will provide this functionality automatically for winforms applications.

Nevertheless, some people have showed an interest in what I came up with, so I’m posting it here for your edification. I hope someone finds it useful.

Usage

To use, simply instantiate the “ApplicationFlickScrolling” class, passing in the datatypes of the container controls you wish to scroll.

For example:

Private Shared moApplicationFlick As New ApplicationFlickScrolling(GetType(Panel))

To switch it on and off, used the “Enabled” property:

moApplicationFlick.Enabled = True

That’s it!

The Implementation

The code consists of 3 classes:

ApplicationFlickScrolling to act as the master controller class
ApplicationMouseEvents class for detecting mouse events
FlickDetector for detecting simple gestures
ScrollController for performing elastic-style easing of scrolling

Improvements

If I’d have continued developing this I would have modified ScrollController to use “proper” easing functions.

Download Sample

Note: The usual disclaimers apply for this code, which has been given freely to help others learn and is not intended for usage in your business application or for running a nuclear facility.

Share this post :

RIAServices – Proudly using SessionState within your DomainServices

anoriginalidea — Fri, 31 Jul 2009 07:17:03 +0000

As mentioned in my previous article How to build huge dynamically loading cross platform Silverlight Business Applications, I’m experimenting with the idea of a hybrid web application that has some parts implement as webforms, others as Silverlight.

A problem I encountered was that RIAService calls did not necessarily access to the same information as my webforms did. An example is “SessionState”. In the case of my company’s framework, the authentication system must be invoked prior to anything else within my domain services. In addition the authentication system needs access to SessionState.

To do this I thought I could inherit from DataServiceFactory and add what I needed. Unfortunately the class is marked as not inheritable. The way around this is to encapsulate the class.

In the code sample below you can see an implementation of MyDataServiceFactory that encapsulates DataServiceFactory and returns an encapsulated HttpHandler that flags to ASP.Net that sessionstate is needed.


Imports System.Web      
Imports System.Web.SessionState 
Public Class MyDataServiceFactory      
    Implements IHttpHandlerFactory       
    Private moHandlerFactory As IHttpHandlerFactory 
    Public Sub New()      
        moHandlerFactory = New System.Web.Ria.DataServiceFactory       
    End Sub 
    Public Function GetHandler(ByVal context As System.Web.HttpContext, ByVal requestType As String, ByVal url As String, ByVal pathTranslated As String) As System.Web.IHttpHandler Implements System.Web.IHttpHandlerFactory.GetHandler 
        Return New MyDataServicesHandler(moHandlerFactory.GetHandler(context, requestType, url, pathTranslated)) 
    End Function 
    Public Sub ReleaseHandler(ByVal handler As System.Web.IHttpHandler) Implements System.Web.IHttpHandlerFactory.ReleaseHandler      
        moHandlerFactory.ReleaseHandler(DirectCast(handler, MyDataServicesHandler).InnerHandler)       
    End Sub       
End Class       
Public Class MyDataServicesHandler       
    Implements IHttpHandler       
    Implements IRequiresSessionState ' Let ASP.Net know that you need to use the session object 
    Public InnerHandler As IHttpHandler      
    Public Sub New(ByVal handlerToWrap As IHttpHandler)       
        InnerHandler = handlerToWrap       
    End Sub       
    Public ReadOnly Property IsReusable() As Boolean Implements System.Web.IHttpHandler.IsReusable       
        Get       
            Return InnerHandler.IsReusable       
        End Get       
    End Property 
    Public Sub ProcessRequest(ByVal context As System.Web.HttpContext) Implements System.Web.IHttpHandler.ProcessRequest      
        ' You can access context.Session here if you want to...       
        InnerHandler.ProcessRequest(context)       
    End Sub       
End Class

Of course to use this, you need to modify the web.config and change the two references to DataServicesFactory to point to your new class instead, which should be hosted in it’s own class library.

Share this post :

How to build huge dynamically loading cross platform Silverlight Business Applications

anoriginalidea — Wed, 22 Jul 2009 00:52:03 +0000

The Silverlight 3 navigation framework provides a really nice way of integrating with the browser history. By default it tends to support a single silverlight control model rather than leveraging the full power of asp.net. In this article I propose an way of structuring applications that utilise asp.net and Silverlight. The approach even allows the use of HTML, WPF-XBAP and Flash as an alternative to Silverlight or in any combination.

Out of the box with Silverlight 3

It seems to me that the Silverlight 3 navigation system works best as a single control embedded in a page (contained in a single xap file). Navigation (and loading of the many parts of an application) happen within that single control. This is similar to the traditional “smart client” architecture.

The Silverlight 3 navigation samples provided allow the straight forward creation of this kind of smart client, with a nice Silverlight themeable container. For simple applications, I recommend people take a look.

To take this even further the Prism framework (which I have found integrates well with Silverlight 3) provides and excellent container framework for those who would like to take this model further.

Dynamically loaded Assemblies in Silverlight 3

In the article “Silverlight 3 Navigation: Navigating to Pages in dynamically-loaded assemblies” , David Poll shows a way of dynamically loading pages into the primary navigation container by using “shim” pages within it.

David describes his strategy as follows:

Load an assembly containing a Page dynamically
Include in this assembly a “shim” Page with no code behind. In its XAML, reference the real page with code behind, and forward any navigation-related information (events, title, query strings, etc.) to that Page
When that page is navigated to, replace the Frame’s content with the real page.
From the application, navigate to the “shim” page in the dynamically-loaded assembly

For a developer, this means creating empty shim pages in the main project for every page they require in other assemblies.

As admitted by the author, this solution is “it’s a bit obtuse, and still harder to do than it ought to be”. I believe David has pushed the Silverlight smart client model as far as it can go.

If you read through the comments section of David’s article “mitkodi” discusses a way of using UriMapping to simplify the solution. This is similar to the approach I’m proposing in this article. (I didn’t see this before)

Perhaps Microsoft will create some markup of some kind to allow cross navigation between assemblies. I hope they do.

Another Way

It seems to me that there are two ways RIA applications can be built, either as a smart client (as described above) or as true web application web pages, each with embedded controls.

In the second approach, each Silverlight page could be embedded on it’s own web page. Navigation could happen at the page level, leveraging the natural navigability of web solutions. The web page could act as a simple “shim” for hosting the RIA content, or it could provide more such as cross-platform and “deep linking”.

In short you would have a solution that is:

Navigable : Navigation could work without the Navigation framework
Cross Platform : An alternate web rendering of it’s content could be provided (which also allows for simpler “deep linking” for SEO)
Modular : If each Silverlight page was on it’s own webpage, each page could have it’s own xap file, with no special workarounds or compromises
Versatile: You can use any Silverlight 3 features you like (including RIA Services for example), using as many or as few assemblies you wish
Not Silverlight Specific : The solution could work for any embedded RIA technology, including Flash (Flex) or WPF-XBAP.

I’ve always thought that combining existing web technologies (DHTML, AJAX, Server side rendering) with RIA would provide something far greater than just an RIA or a web application on their own.

In the the RIA Hybrid example shown in this article, Routing support (introduced in .NET 3.5 SP1) and master pages are used to make the solution simpler.

The RIA Hybrid

In this example, Maria the customer begins at a “home” page, then navigates from this page to a contact enquiry, then to a contact detail.

The Solution

To the Maria it’s just a normal website with normal navigation. They can use browser history and bookmarking work regardless of the browser they are using. Here’s what the solution looks like:

The content Maria sees is actually implemented entirely in Silverlight. In web page“Home.aspx” is a simple web page that provides an alternate web rendering of it’s content if Silverlight is not available.

Here’s the layout xaml of Home.Mainpage,xaml:

Here’s the code of Home.Mainpage.vb:

Private Sub lnkViewContactEnquiry_Click(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles lnkViewContactEnquiry.Click
System.Windows.Browser.HtmlPage.Window.Navigate(New Uri(sender.Tag, UriKind.Relative))
End Sub

As you can see, the code is quite simple and provides an almost html-like approach to navigation.

The code for Home.aspx is also straight forward:

<%@ Page Title="" Language="vb" AutoEventWireup="false" MasterPageFile="~/Container.Master" CodeBehind="Home.aspx.vb" Inherits="WebHybrid.Web.Home" %>


Welcome to Home

    View Contact Enquiry

As you can see, the asp.net page only contains simple html. This means that the developer only has to concentrate on providing the cross-platform rendering of the content. So where’s the Silverlight?

I’ve stored the Silverlight magic in a master page (“Container.Master”) which can be reused with other Shim pages. Basically it checks to see if a matching xbap file exists for the page, and if it does it will render this in a Silverlight host instead of the “ContentPlaceHolder1” web content.

You may notice, that in either case, Maria navigates successfully to ContactEnquiry.aspx. If you look at the solution screenshot above you’ll notice there is not ContactEnquiry.aspx.

The Phantom ContactEnquiry.aspx – Routing

If the developer doesn’t need to provide web content, the cool new .NET3.5 SP1 “Routing” feature comes to the rescue. This feature allows redirection to a generic hosting page if the called aspx doesn’t exist. In this case, GenericSilverlightHost.aspx.

The magic of redirection is accomplished by creating a “Route Handler” class. I haven’t seen any vb.net examples of these on the web, so here’s the code:

Imports System.Web.Routing
Imports System.Web
Imports System.Web.UI
Imports System.Web.Compilation
Imports System.IO
Public Class WebFormRouteHander
    Implements IRouteHandler
    Private msWebFolder As String
    Public Sub New(ByVal path As String)
        msWebFolder = path
    End Sub
    Public Function GetHttpHandler(ByVal requestContext As System.Web.Routing.RequestContext) As System.Web.IHttpHandler Implements System.Web.Routing.IRouteHandler.GetHttpHandler

        Dim lsPage As String = requestContext.RouteData.GetRequiredString("Page") & ".aspx"

        Dim lsFullPathOfPage As String = Path.Combine(msWebFolder, lsPage)
        If File.Exists(lsFullPathOfPage) Then
            Return BuildManager.CreateInstanceFromVirtualPath("~/" & lsPage, GetType(Page))
        Else
            Return BuildManager.CreateInstanceFromVirtualPath("~/GenericSilverlightHost.aspx", GetType(Page))
        End If

    End Function
End Class

It’s wired up with this code in Global.asax:

Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
‘ Fires when the application is started
RouteTable.Routes.Add(New Route("{Page}.aspx", New WebFormRouteHander(Server.MapPath("/"))))
End Sub

Please remember that to get Routing working on your site you will need to modify your web.config file. The easiest way is to search for the word “Routing” in the sample web.config.

So that’s it!

Download the code now and try out the solution, I think you’ll like it.

Conclusion

So developers can create an unlimited number of Silverlight pages, in any number of dynamically loaded xbap assemblies and provide navigation between these.

This rather obvious solution could be taken much further. It could work with other web frameworks such as ASP.Net-MVC or a completely non-Microsoft one. It could work with any RIA technology or combinations of those.

I’m really interested in what people have to say about this approach.

Download the Code

FileDropper Free File Hosting

Links

Silverlight 3 Navigation: Navigating to Pages in dynamically-loaded assemblies – David Poll

Goodbye to Url Rewriting

Share this post :

Silverlight 3 style NavigationContext in WPF

anoriginalidea — Wed, 08 Jul 2009 03:00:04 +0000

At the moment I’m experimenting with various user interface technologies. Because the prototypes are working in parallel, I want to reuse code where possible. With this in mind, I’ve created a couple of useful wrapper functions for navigation in both Silveright 3 and WPF that I thought I’d share.

In case you don’t know the Silverlight 3 Beta now has a navigation framework that works in a similar way to WPF’s Frame navigation feature. To learn more about it, check our Jeff Poise’s great article Silverlight 3’s New Navigation Framework.

I brief, to navigate to a new page and pass a parameters you use a syntax like this in the code behind:


Me.NavigationService.Navigate(New Uri(String.Format(“/SomePage.xaml?someparameter={0}”,somevalue), UriKind.Relative))

In the loaded event of the page you’re navigating to, you use code like this:

Private Sub MyPage_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded txtSomeTextbox.Text = Me.NavigationContext.QueryString("someparameter") End Sub

Nicer Navigating

I found the Navigate method above a little awkward, so in Silverlight I created a little helper function called “NavigateTo”, on page that makes the code a bit nicer.

Me.NavigateTo(“/SomePage.xaml”,”someparameter”,somevalue)

Here’s the implementation:

Imports System.ComponentModel Public Module PageHelper _ Public Sub NavigateTo(ByVal page As System.Windows.Controls.Page, ByVal navigationUrl As String, ByVal ParamArray arguments() As String) Dim lsUrl As String = navigationUrl & "?" Dim lbIsParamName As Boolean = True For Each lsArg As String In arguments lsUrl &= lsArg If lbIsParamName Then lsUrl &= "=" lbIsParamName = Not lbIsParamName Next


        page.NavigationService.Navigate(New Uri(lsUrl, UriKind.Relative))      
    End Sub 
End Module

Nicer NavigationContext

I found Silverlight3’s NavigationContext quite nice to use. Unfortunately this is not available in WPF. I set about creating a helper function that would emulate this functionality in WPF.

WPF Navigation Helper

Here’s a WPF version of PageHelper that allows a compatible syntax with Silverlight3.


Imports System.ComponentModel      
Public Module PageHelper 
    Private WithEvents moCurrentNav As NavigationService      
     _       
   Public Sub NavigateTo(ByVal page As System.Windows.Controls.Page, ByVal navigationUrl As String, ByVal ParamArray arguments() As String) 
        '  Update Navigation Args      
        Dim loNavigationUri As New NavigationContext 
  If arguments.Length > 0 Then        
            For i As Integer = 0 To arguments.Length - 1 Step 2         
                 loNavigationUri.QueryString.Add(arguments(i), arguments(i + 1))         
            Next 

            End If
            
        loNavigationUri.Uri = New Uri(navigationUrl, UriKind.Relative) 
        ' Strip the Xaml extension  
        Dim lsClassName As String = navigationUrl.Substring(0, navigationUrl.Length - 5)  
        ' Make my class name  
         Dim lsName As String = page.GetType.Namespace & "." & lsClassName  
        ' Instantiate the class  
        Dim loPage As Page = page.GetType.Assembly.CreateInstance(lsName)  
        ' Do the Navigation  
         page.NavigationService.Navigate(loPage, loNavigationUri)       
     
        ' Store the current NavigationService so we can complete      
        moCurrentNav = page.NavigationService 
    End Sub      
     _       
Public Function NavigationContext(ByVal page As System.Windows.Controls.Page) As NavigationContext       
        Return moLastNavContext       
    End Function       
    Private Sub moCurrentNav_Navigated(ByVal sender As Object, ByVal e As System.Windows.Navigation.NavigationEventArgs) Handles moCurrentNav.Navigated       
        moLastNavContext = e.ExtraData       
        moCurrentNav = Nothing       
    End Sub       
    Private moLastNavContext As New NavigationContext 
End Module      
Public Class NavigationContext       
    Public QueryString As New Dictionary(Of String, String)       
    Public Uri As Uri       
End Class

I also have provided primitive support for cross-assembly navigation.

I hope someone found this useful, let me know.

Share this post :