Today I got chance to work with TestComplete to automate a Silverlight application.
If you need to get the support for Silverlight object recognition you need to patch your xap with a TestComplete utility. The patch just adds 2 dlls into your xap and updates the AppManifest.xaml file.
We have an application which uses same code base for WPF as well as Silverlight .Hope our WPF test scripts will execute for testing Silverlight version as well.
After a while I had to conduct training in my company.Earlier it was WPF and now the topic is Silverlight.I dont know whether Silverlight training is relevant now because of HTML 5.According to me next version of ASP.Net may be 5.0 or 6.0 will emit html5 which may reduce the need of Silverlight in the RIA world.But in other context Silverlight is valuable because of Windows 7 mobile development.
Anyway I have started training and conducted one small test in order to evaluate my students.I am not going to share their scores but some questions I have asked.
If you are a Silverlight developer you may feel that some questions are silly or too simple.But my students are in different categories.Some had projects in Silverlight others are hearing word Silverlight for the first time.So its a mix and people can just start learning concepts even if they are not able to answer.
Hope I don’t have to provide answers to these questions since all are known.Let me know if anybody needs clarification.
NB: These are not Silverlight interview questions and I think nobody will ask these type of questions in interview.
So many times I have seen this type of messages in dev environment.Now understood what was the reason..I was doing the same without knowing the actual facts.
Here is the post which gives you how to get the Silverlight version through Javascript.
http://www.kunal-chowdhury.com/2010/09/how-to-detect-installed-silverlight.html
If you want to get the Silverlight version inside Silverlight code you may invoke this function as follows.
http://silverlightedweb.blogspot.com/2008/05/silverlight-javascript-communication.html
The below link explains the security aspects of Silverlight. ie differences among the Transparent code,Safe critical code and Critical code along with the theory of user initiation.
http://msdn.microsoft.com/en-us/library/dd470128%28VS.95%29.aspx
In my general code blog I talked about usage of dynamic keyword in Silverlight browser interaction applications.Here is the sample with source.
Generally the browser interaction is used to communicate with the browser elements from Silverlight application.Its not at all type safe.So we use the general methods like SetProperty to talk to the com objects.
The 'innerText' property isn't defined at compile-time - it's a Javascript property on the div. The way to do this without the dynamic keyword is:
var myDiv = HtmlPage.Document.GetElementById("myDiv");
myDiv.SetProperty("innerText", "Text was replaced!");
dynamic myDiv = HtmlPage.Document.GetElementById("myDiv");
myDiv.innerText = "Text was replaced!";
Download the sample from here
I know the title is confusing.You will know why I gave this title when you read further.When we talk about the Rich Internet Application we could see that they are half desktop and half web.The UI resembles a desktop application but they behave like web applications.
As we know all the desktop applications comes with a help.We all would like to have a help popup on F1 key when we are struck on a desktop’s functionality. The same applies to RIA.Due to its richness like desktop we should have a F1 help window.This post talks about implementing a F1 help window for Silverlight applications.
Basically we need to capture the F1 key and show a popup.I don’t think people expects a huge hlp file on F1 because this is web and downloading a big file will take time.So better we can choose html or asp.net based help which are context based and easy to load. Now the things are simple just show a html popup on F1 press.
Here I am adding one good feature of Silverlight.Attached properties. This extends one class by introducing a new property implemented in another class.I am not going into details of attached properties.We can write a HelpProvier class which holds the attached property so that we can set the help source as follows from anywhere in our application.
<UserControl x:Class="F1Help.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:F1Help">
<Grid x:Name="LayoutRoot" Background="White" local:HelpProvider.Source="help.htm">
<TextBox Text="Enter the datas here"></TextBox>
</Grid>
</UserControl>
using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Browser;
namespace F1Help
{
public class HelpProvider
{
public static Uri GetSource(DependencyObject obj)
{
return (Uri)obj.GetValue(SourceProperty);
}
public static void SetSource(DependencyObject obj, Uri value)
{
obj.SetValue(SourceProperty, value);
}
public static readonly DependencyProperty SourceProperty =
DependencyProperty.RegisterAttached("Source", typeof(Uri), typeof(HelpProvider), new PropertyMetadata(OnSourcePropertyChanged));
public static void OnSourcePropertyChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (e.NewValue != null && e.NewValue is Uri)
{
FrameworkElement element = sender as FrameworkElement;
element.KeyDown+=new KeyEventHandler(element_KeyDown);
}
}
static void element_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.F1)
{
e.Handled = true;
e = null;
if (GetSource(sender as DependencyObject) != null)
{
ShowHelpFile(GetSource(sender as DependencyObject));
}
}
}
private static void ShowHelpFile(Uri source)
{
HtmlPage.Window.Navigate(source, "new");
}
}
}
function HideHelp() {
document.onhelp = function () { return (false); }
window.onhelp = function () { return (false); }
}
Everybody knows that there is Out of browser support in Silverlight 3 and Silverlight 4.Basically how it is working? Its simple.It downloads the xap file into a local folder and runs the xap from that location as similar to in browser.But with some more privileges.
All that are fine.So to which location the xap files is getting downloaded in my local machine? It’s very easy to find out.Right click on the OOB application icon in desktop and get select properties.You can get the application id.Using that application id you can find the application folder in the Out-of-browser cache in the below location.
C:\Users\<login id>\AppData\Local\Microsoft\Silverlight\OutOfBrowser
Got the below lab when I was looking for the usage of RichTextBox in Silverlight 4.This gives an idea how to use RichTextBox.
http://channel9.msdn.com/learn/courses/Silverlight4/NewFeatures/RichTextBox/
More labs here
If you are a Silverlight developer there is a chance that you may get the exception “Parser internal error: Object writer 'xClassNotDerivedFromElement'” very rarely which is difficult to track.Even you can’t put break points to track this.As a developer you will google the same.But most probably you will not get any results.
Only thing went wrong here is the namespace.But this is not at all mentioned in any of the exception details.ie The project which you are working on will not have a namespace or somebody in the project might forgot put the namespace in XAML or code files.
So make sure that there is namespace present in the project and the xaml files are correctly mapped to the corresponding code files in the x:Class attribute.
Note : We cannot have Silverlight projects without namespace.
I came to see this exception when one of my colleagues tried to write code which should compile in both Silverlight 4 and WPF 4.
The problem : Creating WCF proxy in Silverlight without using the add service reference and it’s auto generated code
It was a debate that whether we can call a WCF service from Silverlight without using “Add Service Reference” menu item.In WPF or in the other .Net environments it is easy.We just need to refer the contracts dll and write a class which inherits from ClientBase.But this is Silverlight - A different runtime.
A Normal WCF service reference with all the generated code files
There were 3 opinions.Not at all possible,Possible with less amount of code,Possible if we create all those classes by our own.Just avoid the last one because that doesn’t give us any benefit as it is just making the process manual.
One of my Colleagues started research on that and was able to achieve the same.I am just sharing the idea.
Solution : We can achieve the same using contract interface,proxy class and a custom eventargs class
First of all there are no changes at the server side.Only 3 types we are going to write at client side which will be present in the reference.cs file if you create the proxy using “Add Service Reference” Dialog.
There will be a question for sure.Why are we writing the code which is being auto generated ? Why don’t we create a reference using the dialog and copy paste the reference.cs code?
The answer for both the questions is same.You can create reference using the dialog and get the code from reference.cs.That is enough.
Advantages
Implementation steps
Lets take example of implementing a DataService with one method GetData which returns a string.Don’t bother about the server side.Use the same.Below are the steps to perform at client side ie Silverlight side.
Imports System.ServiceModel
<ServiceContract()> _
Public Interface IDataService
<OperationContract(AsyncPattern:=True)> _
Function BeginGetData(ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult
Function EndGetData(ByVal result As System.IAsyncResult) As String
End Interface
Public Class GetDataCompletedEventArgs
Inherits System.ComponentModel.AsyncCompletedEventArgs
Private results() As Object
Public Sub New(ByVal results() As Object, ByVal exception As System.Exception, ByVal cancelled As Boolean, ByVal userState As Object)
MyBase.New(exception, cancelled, userState)
Me.results = results
End Sub
Public ReadOnly Property Result() As String
Get
If Me.results IsNot Nothing Then
Return CType(Me.results(0), String)
End If
Return Nothing
End Get
End Property
End Class
Public Class DataServiceProxy
Inherits ClientBase(Of IDataService)
Implements IDataService
#Region " Constructors"
Public Sub New()
MyBase.New()
End Sub
Public Sub New(ByVal endpointConfigurationName As String)
MyBase.New(endpointConfigurationName)
End Sub
Public Sub New(ByVal endpointConfigurationName As String, ByVal remoteAddress As String)
MyBase.New(endpointConfigurationName, remoteAddress)
End Sub
Public Sub New(ByVal endpointConfigurationName As String, ByVal remoteAddress As System.ServiceModel.EndpointAddress)
MyBase.New(endpointConfigurationName, remoteAddress)
End Sub
Public Sub New(ByVal binding As System.ServiceModel.Channels.Binding, ByVal remoteAddress As System.ServiceModel.EndpointAddress)
MyBase.New(binding, remoteAddress)
End Sub
#End Region
#Region "GetData"
Private onBeginGetDataDelegate As BeginOperationDelegate
Private onEndGetDataDelegate As EndOperationDelegate
Private onGetDataCompletedDelegate As System.Threading.SendOrPostCallback
Public Event GetDataCompleted As System.EventHandler(Of GetDataCompletedEventArgs)
Public Function BeginGetData(ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult Implements ServiceContracts.IDataService.BeginGetData
Return MyBase.Channel.BeginGetData(callback, asyncState)
End Function
Public Function EndGetData(ByVal result As System.IAsyncResult) As String Implements ServiceContracts.IDataService.EndGetData
Return MyBase.Channel.EndGetData(result)
End Function
Private Function OnBeginGetData(ByVal inValues() As Object, ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult
'Dim engID As String = CType(inValues(0), String)
'Dim libraryID As String = CType(inValues(1), String)
'Dim folderName As String = CType(inValues(2), String)
'Dim parentFolder As PathInfo = CType(inValues(3), PathInfo)
'Dim folderGeneralProperties As FolderGeneralProperties = CType(inValues(4), FolderGeneralProperties)
'Dim additionalProperties As System.Collections.Generic.Dictionary(Of String, String) = CType(inValues(5), System.Collections.Generic.Dictionary(Of String, String))
Return CType(Me, IDataService).BeginGetData(callback, asyncState)
End Function
'Private Function GetData() As String Implements IDataService.GetData
'Return MyBase.Channel.GetData()
'End Function
Private Function OnEndGetData(ByVal result As System.IAsyncResult) As Object()
Dim retVal As String = CType(Me, IDataService).EndGetData(result)
Return New Object() {retVal}
End Function
Private Sub OnGetDataCompleted(ByVal state As Object)
'If Not (GetDataCompleted Is Nothing) Then
Dim e As InvokeAsyncCompletedEventArgs = CType(state, InvokeAsyncCompletedEventArgs)
RaiseEvent GetDataCompleted(Me, New GetDataCompletedEventArgs(e.Results, e.Error, e.Cancelled, e.UserState))
'End If
End Sub
Public Overloads Sub GetDataAsync()
If (Me.onBeginGetDataDelegate Is Nothing) Then
Me.onBeginGetDataDelegate = AddressOf Me.OnBeginGetData
End If
If (Me.onEndGetDataDelegate Is Nothing) Then
Me.onEndGetDataDelegate = AddressOf Me.OnEndGetData
End If
If (Me.onGetDataCompletedDelegate Is Nothing) Then
Me.onGetDataCompletedDelegate = AddressOf Me.OnGetDataCompleted
End If
MyBase.InvokeAsync(Me.onBeginGetDataDelegate, New Object() {}, Me.onEndGetDataDelegate, Me.onGetDataCompletedDelegate, Nothing)
End Sub
#End Region
End Class
Uploaded a sample which does the same.
Here are some details about the installation issues which I faced when tried to setup my machine for Silverlight 4 with Visual studio 2010. No need to read further, if you are able to setup your machine with Silverlight 3 + VS 2008 and Silverlight 4 + VS 2010 without issues ;-)
After the completion of previous project which is done in VSTS 2008 and Silverlight 3 we decided to port the same to Silverlight 4.According to my knowledge it is difficult to have 2 versions of Visual studio if any version of them are in beta.Here to work with Silverlight 4 we need Visual studio 2010 beta 2.So normally I uninstalled Silverlight 3 and started uninstalling VS 2008.
Everything went fine until my onsite counterpart called and asked me to setup my machine with VS 2008 + Silverlight 3and VSTS2010 beta 2 + Silverlight 4 beta .The reason was simple.We may need to support client for the previous project.The good news was he setup his machine with the above mentioned configuration.
So I stopped the uninstallation of VSTS 2008.Seems the problems started here.Started installation of Silverlight 3.Got the simple error message.Not able to complete the installation.Log says a previous version of Silverlight is there.Tried with different versions of Silverlight 3 which were available with colleagues.Hours passed with Uninstallations, Installations and reboots.Finally downloaded the Silverlight 3 version from net and tried.That too not worked out.
As usual I asked Google what is this error message by pasting the installation log in search box.Got a good link with Silverlight error messages and their solutions.
Silverlight 3 installation Error messages : http://blogs.msdn.com/amyd/archive/2009/03/19/silverlight-tools-installation-error-codes.aspx
I figured out that there are 2 patches which are stopping me from installation.They are KB967143 and KB956453 and the solution was to manually uninstall those.But when I tried uninstalling it said “Update removal was disallowed by policy”.What policy ? Its My machine and my login with admin privileges.I haven’t set any policy.
After a google I came to know more things about the patches.There are different types of patches and these patches fall into UNINSTALLABLE patch category.The only solution was to reinstall the application without applying those patches.
Uninstallable patches:http://msdn.microsoft.com/en-us/library/aa372102%28VS.85%29.aspx
Again uninstalling and installing VS 2008.Then Silverlight 3.Next series was VS 2010 beta 2 and Silverlight 4 beta.Tested whether the old project is running or not in VS 2008 and creation of Silverlight 3 and 4 projects in VS 2008 and VS 2010 respectively.Overall cost - a weekend and 2 week days.
Sometimes I am getting error message “VB.Net compiler is not responding” when I compile Silverlight 3 projects in VS 2008.But not consistent.Other than that everything works perfect.
As I told in the last post ,I have started with the Silverlight 4 research using Visual Studio 2010 beta 2 .The first thing I noted is the add reference box in Silverlight project is empty.
According to Microsoft this is a bug and has fixed.
Workaround
In the add reference dialog manually browse the dll from the folder [Install Drive]:\Program Files\Microsoft SDKs\Silverlight\v4.0\Libraries\Client
https://connect.microsoft.com/VisualStudio/feedback/details/520040/missing-list-of-components-from-add-reference-in-silverlight-4-0-projects
http://forums.silverlight.net/forums/p/150240/335233.aspx
I was not able to blog more after joining my current company because of an important project.That project was in Silverlight 3 to show an existing big business application can be ported to Silverlight 3 and runs properly.
We achieved our goal this week and the client accepted the same.According to my small experience that project will be the biggest business application ever built using Silverlight or even RIA technologies.Sorry I am not in a position to tell any more details about that application due to NDA.
Anyway we are progressing to port the same to Silverlight 4 and the research for that is already started. Thats it for now.Stay subscribed for more news.
It seems the days of HTML overlay is coming to an end.A pdf viewer for Silverlight is ready by first floor software who gives Silverlight spy.Read the details here.
See it in action here
After joining in new company I rarely get time to learn new technologies than my previous company.Obviously its due to more responsibilities.But this week end I was managed to find some time to learn MEF (Managed Entity Framework) which was introduced some time back.
In simple words its all about Export,Import and Composition.ie you export a type or property then you import into another property which is present in another class.For this to happen there should be somebody in the middle.That is composition.
The export and import takes place by using attributes.Just decorate the class or property with the attribute export or import to achieve the functionality.For composition you just need one line code :-)
Exporting one type
[Export("Emp")]
public class Employee
{
}
The above code just exports one class.Lets see how this is being used or imported.
public class EmployeeViewModel
{
[Import ("Emp")]
public Employee Current { get; set; }
}
The employee view model class receives the exported type as Current.This code it not completed.To complete the code we need to compose.It is done by the line below.
public EmployeeViewModel()
{
PartInitializer.SatisfyImports(this);
MessageBox.Show(Current.ToString());
}
This is the constructor of EmployeeViewModel class and the first line does the composition and after that if we access the object it will be initialized and ready for use.In this case it will display the default ToString method’s output ie the class name.
This is the basic concept of MEF.This can be used in data binding and for collection types etc…Next time will discuss about a data binding and MEF.
The project contains a reference to the dll System.ComponentModel.Composition.dll.You can locate this file from the attached sample or in the Silverlight 4 installation.
Sample can be downloaded from here.
Just now got a good link in MSDN for performance optimization in Silverlight 3 applications.
http://msdn.microsoft.com/en-gb/library/cc189071%28VS.95%29.aspx
Don’t know when can I get a chance to apply this in my current project :-(
