ganshani.com » Silverlight

Silverlight Interview Questions – I

Punit Ganshani — Fri, 12 Feb 2010 09:20:21 +0000

Hello folks,

Marching forward, I will post a series of Interview Questions on Silverlight. This will cover questions at each level – easy, intermediate and advanced. And I am sure, other sites & users would post these on many other sites too

So keep watching this space. Some questions below to start with

Level: Developer

What is the role of Silverlight Plugin in the Silverlight Application Life-Cycle?
What does the keyword ‘type’ signify in the Silverlight Hosting page.
You have developed an application on Silverlight 2, will it execute on Silverlight 4 platform? Is vice-versa true?
Your organization has blocked download of any software from Internet and you want to deploy your Silverlight Application as Intranet Application. The users do not have Silverlight plugin installed on their machine; however you have the installable. How do you plan to deploy your application? Will you change the application code to fit this requirement or change the organization policy?
Your Silverlight application faces some technical errors while it is executed. Where will you write your code to get notification of these errors?
Can any Silverlight Application be viewed on Linux? Or a specific installation is required?
Assume your host page defines the background as White
while your MainPage.xaml (that loads initially) defines background as ‘Gray’
What will be the color of the background?
I have two actors to a Silverlight Application – Employee and Customer. The default page (default.html) should always open Customer view; whereas \view\employee.html should open Employee view.How would you implement this?
What is significance of initParams in

Customizing Splash Screen in Silverlight

Punit Ganshani — Wed, 10 Feb 2010 08:12:59 +0000

Customizing Splash Screen (a screen that loads before the Silverlight application loads) requires some development effort in the host application (could be HTML/ASPX/any other application).

Creating SplashScreen.xaml

First, we create a XAML file – say SplashScreen.xaml file which displays two things – a progress bar and a textblock that displays ‘% completed’


http://schemas.microsoft.com/client/2007"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

Here, we have a baseBackground (that forms background) that is Black in color and small bar that will move ‘movementBar‘ which is Gray in color.

As the page downloads the data, movementBarTransform needs to be changed, so that the movementBar appears as if it is increasing. And simultaneously, progressText should display the % downloaded.

Modifying host file

Now let’s modify the host file that loads the Silverlight Application.



   
   
   
   
   
   
   http://go.microsoft.com/fwlink/?LinkID=115261" style="text-decoration: none;">
        http://go.microsoft.com/fwlink/?LinkId=108181" alt="Get Microsoft Silverlight" style="border-style: none"/>

The most important line that calls a JS function ‘onSourceDownloadProgressChanged’ when some part (bytes) of the XAP is downloaded is:

Adding JS in hosting file


function onSourceDownloadProgressChanged(sender, eventArgs)
        {
       
         sender.findName("progressText").Text = Math.round((eventArgs.progress * 100)) + "% downloaded ...";        
         sender.findName("movementBarTransform").ScaleX = eventArgs.progress;        
        }

This code snippet calculates the percentage of XAP file downloaded and displays it in the textbox. It also increases the ScaleX property of ScaleTransform of movementBar as per the progress.

Testing the Splash Screen

Now, add some heavy sized ZIP file in the Silverlight application so that your XAP file becomes atleast 5 MB and try to execute the application.

What you would see is a new custom Splash Screen

ClientAccessPolicy Sample

Punit Ganshani — Thu, 21 Jan 2010 13:35:16 +0000

Recently I have delivered a 4-day training session on Silverlight 4 and many participants asked for a sample ClientAccessPolicy.xml file. So this is for those who want it

Just change the “*” to “*.xyz.com” to restrict permissions to request originating from xyz.com

Happy creating of WCF services for Silverlight & Flash..

NotificationWindow in Silverlight (Out of Browser Apps)

Punit Ganshani — Wed, 13 Jan 2010 05:58:06 +0000

Silverlight 4 brings another feature to desk – NotificationWindow. NotificationWindow is different from PopUp in following ways:

NotificationWindow opens as a Splash Screen, while PopUp does not.
NotificationWindow has an expiry time (set in MilliSeconds); while PopUp needs to be closed explicitly
NotfificationWindow can be implemented only for Out-Of-Browser applications; PopUp can be used for both Web and Out-Of-Browser applications

With that, let’s see how to implement NotificationWindow for Silverlight Applications.

Statement – Create NotificationWindow to denote a Upgrade Window

First, we will design a NotificationWindow – Create a New Silverlight UserControl and give it name: UpgradeWindow

Next, we define a Model class for UpgradeWindow – UpgradeWindowModel.cs


public class UpgradeWindowModel : INotifyPropertyChanged
    {
        private string _title;
        public string Title
        {
            get
            {
                return _title;
            }
            set
            {
                _title = value;
                OnPropertyChanged(value);
            }
        }

        private string _content;
        public string Content
        {
            get
            {
                return _content;
            }
            set
            {
                _content = value;
                OnPropertyChanged(value);
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        public void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

Further, we invoke this UpgradeWindow in our MainPage.cs


public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            LoadPopUpWindowInOutofBrowser();
        }

        private void LoadPopUpWindowInOutofBrowser()
        {
            NotificationWindow win = new NotificationWindow();
            UpgradeWindow un = new UpgradeWindow();
            un.DataContext = new UpgradeWindowModel { Title = "Checking for upgrades",
                                                    Content ="Downloading content..." };
            win.Width = un.Width;
            win.Height = un.Height;
            win.Content = un;
            win.Show(10000);
        }
    }

And, the NotificationWindow will be displayed when the application is executed.

Right Click in Silverlight 4

Punit Ganshani — Tue, 12 Jan 2010 06:27:47 +0000

Let’s discuss yet another feature of Silverlight 4 – right click! This was most wanted feature and Microsoft has really blessed the Silverlight world by giving this feature!

Our solution will display a red colored box. User can right click within the area of the red box to customize it. On right click, a pop up will be displayed which will allow the user to change the width & height of the red box. This is the simplest example to demonstrate right click in Silverlight 4

The design part (XAML):-

The C# code for this XAML is:

namespace SilverlightRightClick
{
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
}

private void frame_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
e.Handled = true;
}

private void frame_MouseRightButtonUp(object sender, MouseButtonEventArgs e)
{
pop.HorizontalOffset = e.GetPosition(null).X + 2;
pop.VerticalOffset = e.GetPosition(null).Y + 2;
pop.IsOpen = true;
}

private void slheight_ValueChanged(object sender, RoutedPropertyChangedEventArgs e)
{
if (frame == null) return;
frame.Height = slheight.Value;
}

private void slWidth_ValueChanged(object sender, RoutedPropertyChangedEventArgs e)
{
if (frame == null) return;
frame.Width = slWidth.Value;
}

private void btnDone_Click(object sender, RoutedEventArgs e)
{
pop.IsOpen = false;
}
}
}

Just execute this code and right click on the red colored box!

Printing in Silverlight 4

Punit Ganshani — Mon, 11 Jan 2010 05:46:30 +0000

Another cool feature that Microsoft has included in Silverlight 4 is the ability to Print any UI Element to any printer and that too, without any complicated code. Let’s have a quick look at implementing this.

Printing starts with the PrintDocument class. This class exposes several events – we shall use only one at this moment – that are used to call back to ask you about how to print individual pages.

Initial code:


PrintDocument docDataGrid = new PrintDocument();
docDataGrid.DocumentName = "Data Grid Print using Silverlight 4";
docDataGrid.PrintPage += new EventHandler(docDataGrid_PrintPage);
docDataGrid.Print();

We first defined a friendly DocumentName. This DocumentName is displayed in the Printer Spooler when printing starts. PrintPage is the core function that is invoked when page is printed, so formating and assigning of content should be done in this function.


void docDataGrid_PrintPage(object sender, PrintPageEventArgs e)
{

// Stretch to the size of the printed page

dataGrid1.Width = e.PrintableArea.Width;

dataGrid1.Height = e.PrintableArea.Height;

// Assign the XAML element to be printed

e.PageVisual = dataGrid1;

// Specify whether to call again for another page

e.HasMorePages = false;

}

What’s happening here? Initially we are resizing the control to be printed (here dataGrid1) to the size of PrintableArea. This ensures that the page does not remain blank.

Then, we assign the PageVisual property to the element that needs to be printed. If this is skipped, no content will be printed.

HasMorePages flag indicates whether there are set of trailing pages that need to be printed as well. If this is set to true, the same method (docDataGrid_PrintPage) will be invoked again.

Loading ResourceDictionary in Silverlight

Punit Ganshani — Thu, 07 Jan 2010 06:47:05 +0000

ResourceDictionary in Silverlight consists of styles, pallates, and other static resources.

These static resources – styles – can be bound to UIElements in the view when the view is loaded. However once the view is loaded, any change in the resources will not affect the loaded view. Views that are loaded after the change in resource dictionary will undergo the changes. Let’s take an example:

There are two ResourceDictionary files. One defines the background of Button as ‘Black’ and the other defines it as ‘White’

Initially, Black RD is applied so when the view is created, button (btnButton1) appears black.

Now lets apply White RD dynamically. This will not change the color of already loaded button (btnButton1) and it will appear as Black.

But any Button that is loaded after this change (application of White RD) will appear White in color.

Now the question comes, how to achieve this change behavior dynamically – through C# code – lets see that.


ResourceDictionary dictionary = Application.Current.Resources as ResourceDictionary; XDocument xaml = XDocument.Load(@"WhiteTheme.xaml");
ResourceDictionary rd = XamlReader.Load(xaml.ToString()) as ResourceDictionary;
dictionary.MergedDictionaries.Clear();
dictionary.Clear(); dictionary.MergedDictionaries.Add(rd);

This code snippet will load the WhiteTheme.xaml (a ResourceDictionary file) dynamically by removing the existing applied ResourceDictionary (BlackTheme.xaml)

Dynamic Theme in Silverlight 3

Adieu 2009!

Punit Ganshani — Mon, 04 Jan 2010 09:09:20 +0000

Fifty five! That is 79% more activity on ganshani.com than activities before the year 2009! This means more information on this site, better & more code, more visitors, and more knowledge transfer.

2009 was a real good year for the readers of this site. We are glad to have added 55 posts in this year.. All focusing majorly on three areas:

Silverlight – 25 posts – 45.5 %
Winform – 19 posts – 34.5 %
Off-track – 11 posts – 20 %

The average time on site increased with 87.74% new visitors to the site – this surely means, that the areas of concentration are much liked by.

10 most visited links in the order of popularity:-

Silverlight Training Kit
Dynamic Themes in Silverlight 3
Bluetooth with C#
Installation Error Code Silverlight - 0×80091007-the-hash-value-is-not-correct
List vs Observable Collection
Date Format in ASP.NET
Hosting Silverlight as Desktop Applications – One and Two
Exception MessageBox in C#
Silverlight Best Practices – One, Two, Three, Four
Floating Container in Silverlight

What more.. The site saw a newer look with lot of great features like

Better Look and Feel with WPCandy Theme
Fantastic Gallery
Twitter, Facebook, MySpace integration,
Contact form for quicker information,
3 Training Kits – Silverlight, DLINQ and NDoc
and got listed @ BlogAdda

So with lot of movement, we are ready to scale newer heights in 2010. But this needs a continued support from you. Let us know what you wish to have on our site…

Wishing you a happy new year!

Silverlight 4 Security Overview White Paper

Punit Ganshani — Mon, 28 Dec 2009 12:29:03 +0000

I came through a wonderful link that focuses on Security with Silverlight 3 and Silverlight 4 applications. Kudos to Nick, who has explained this wonderfully…

For all my readers, do read this post… Its wonderful!

@Nick: Thanks man!

Link: http://blogs.msdn.com/nickkramer/archive/2009/11/20/silverlight-4-security-overview-white-paper.aspx

RichTextBox in Silverlight 4

Punit Ganshani — Thu, 24 Dec 2009 04:39:11 +0000

I was trying my hands on Silverlight 4 Beta version and found this is wonderful control – RichTextBox.. This was much needed on Web Platform and Microsoft has really made it work simple… Rather, thanks to the invention of XAML!

This small control supports many features. Some of them are:

Formatting of text at runtime – font, color, bold, italics, underline, etc.
Addition of inline UI Elements in the Text Box itself.
Read / Write only modes both supported.
Hyperlinks can also be inserted in the text.

Let’s do some scripting. Two ways to work:-

Way 1: Texting through XAML

This is a sample text.




 This is a sample text.

Way 2: Texting through C# Code


// Create a Run of plain text and some bold text.

Run myRun1 = new Run();

myRun1.Text = "This is a ";

Bold myBold = new Bold();

myBold.Inlines.Add("sample");

Run myRun2 = new Run();

myRun2.Text = "text.";

// Create a paragraph and add the Run and Bold to it.

Paragraph myParagraph = new Paragraph();

myParagraph.Inlines.Add(myRun1);

myParagraph.Inlines.Add(myBold);

myParagraph.Inlines.Add(myRun2);

// Add the paragraph to the RichTextArea.

richTextBox.Blocks.Add(myParagraph);

//Add the RichTextArea to the StackPanel.

stackPanel.Children.Add(richTextBox);

Hope this helps!

ganshani.com » Silverlight

Silverlight Interview Questions – I

Related posts:

Customizing Splash Screen in Silverlight

Creating SplashScreen.xaml

Modifying host file

Adding JS in hosting file

Testing the Splash Screen

Related posts:

ClientAccessPolicy Sample

Related posts:

NotificationWindow in Silverlight (Out of Browser Apps)

Related posts:

Right Click in Silverlight 4

Related posts:

Printing in Silverlight 4

Related posts:

Loading ResourceDictionary in Silverlight

Related posts:

Adieu 2009!

Silverlight 4 Security Overview White Paper

Related posts:

RichTextBox in Silverlight 4

Related posts: