Wpf Wonderland

At PDC 2009 recently, we heard that the Silverlight 4 beta release is available for download. This tip gives a quick overview of the new features.

From a modest start less than three years ago, Silverlight has grown into a serious competitor in the rich Internet client space. Currently it is installed on 45% percent of all internet connected devices. In some areas of the world, most notably Europe, the number climbs to 60%. For another important indicator in the growing influence of Silverlight just look around the Internet and tally up the companies betting on this new technology; over 350 partners in all. These companies are placing a strategic bet on Silverlight for several reasons, including:

• One, Microsoft is a dominant player in many technologies and it seems likely that the Silverlight platform will be a success.
• Two, Silverlight is similar to other Microsoft frameworks, like WPF, and is programmed in familiar Microsoft languages like Visual Basic and C#.
• Three, Silverlight is filled with compelling feature that simplifies building modern graphic rich applications. With Silverlight 4 these features get even better.

To get started you’ll need to download and install the following:

• Visual Studio 2010 Beta 2
• Silverlight Tools for Visual Studio 2010
• Expression Blend for .NET 4 Preview

Silverlight 4 is bursting with enhancements and new features. Here’s are some of the highlights.

New CLR
Silverlight 4 now includes the soon to be released.NET 4 runtime. This means new features like support for Dynamic objects.

Printing
Silverlight 1 shipped with no print support. Immediately Microsoft was flooded with requests to add this feature. It took a few releases but Microsoft finally has a printing API in Silverlight.

public void SampleCode()
{
 var doc = new PrintDocument();
 doc.DocumentName = "Printing the Grid";

 // wire up event which will print UI
 docToPrint.PrintPage += PrintUi;

 docToPrint.Print();
}
public void PrintUi(object s, EventArgs e)
{
 e.PageVisual = this.MainGrid;
}

Better controls

The included control count keeps rising– here are a few of the new controls.

BusyIndicator: A simple ‘waiting’ screen that informs users of a pending task.

RichTextArea: Embed complex text, image and lists in your Silverlight application. Note that this is a separate control from the WebBrowser control, which permits usage of HTML.

Charting: Though Microsoft’s chart offering is not as complete as the third party vendor chart packages their charts handle the most common data visualization needs.

Accordion: A collection of collapsible areas.

LayoutTransformer: Applies a transform to its embedded content.

Rating: Displays a rating picker which is customizable with your own images.

Time Picker: Allows the user to select a time from a dropdown.

New Themes: 11 new themes are available for sprucing up your control set.

Bi-Directional Support: Silverlight controls now support bi-directional text and left-to-right layout.

Languages: Thirty new languages are now supported, including Thai, Hebrew and Arabic.

Other improvements

• Silverlight now loads applications quicker than Silverlight 3 and improves runtime performance by up to 200%.
• Cut and paste now work as expected in most client side applications.
• Drag and drop is now available, allowing users to drag content into the Silverlight application.
• Mouse interaction is better with right click events and mouse scrolling capabilities added.
• If the user’s monitor is multi-touch aware you can capture the multi-touch input in your Silverlight application.
• Deep Zoom now uses hardware acceleration, which results in faster animation and support for larger datasets. For an interesting use of Deep Zoom and Photo Synth see Microsoft Pivot; a new data visualization system that works with huge datasets.
• Google Chrome browser support.

In addition to the Silverlight bits, there are beta releases available for related tools like WCF RIA Services, Visual Studio 2010, Silverlight Toolkit and Expression Blend 4. So, there’s a lot for us Silverlight users to explore.

[Original article on TechTarget.com]

Application developers are constantly pushing the boundaries between Web applications and client applications. Why?  Because want our Web apps to work more like client apps and vice versa. But Web application developers must face the security implications inherent in the Web deployed model. The big question, how much trust should be granted to an Internet application?

Silverlight is a great case in point. Imagine that your Silverlight application requires access to the user’s webcam or you wish to write files into the My Music folder. Silverlight is a Web technology, or at least is deployed via a browser. To mitigate security concerns, Silverlight is constrained to run in a sandbox. This sandbox restricts what the Silverlight application can do to the local computer. This is sensible as administrators need assurance that Silverlight applications won’t commandeer the system. But this also means that sandboxed applications are walled off from accessing local devices, like hard drives and webcams for example.

Types of Out Of Browser applications
Silverlight 3 blurred the line between online and offline applications by enabling the Out Of Browser (OOB) setting. In version 3 you can take your application out of browser which permits the user to enjoy your application while disconnected from the network. Version 4 ramps up the features available to OOB applications.

Living in the sandbox

HTML Hosting: It’s now possible to include embedded HTML within your Silverlight application. Use the new WebBrowser control as follows:

<WebBrowser x:Name="bannerAdControl" Width="300" Height="200" />
<!--  add html to webbrowser control -->
bannerAdControl.NavigateToString("<h1>Download Silverlight now.</h1>");

Under the hood the WebBrowser control uses WebKit on the Mac and the IE browser control on Windows.

OOB Window settings: Silverlight 4 offers full control over window settings such as start position and size.

Popup Notifications: You’re probably familiar with the animated ‘toast’ window that is used by Windows application to provide real-time notifications from email clients. Here’s how to launch a notification from an OOB application.

var nw = new NotificationWindow();
nw.Width = nw.Height = 300;

var cn = new CustomNotificationWindow();
cn.Header ="New Mail";
cn.Text ="You have new mail!";
. . .
nw.Contents = cn;
nw.Show(3400);

Requesting elevated privileges

Silverlight 4 has a number of new features that need elevated privileges. For security reason this can only be granted if the user consents to an elevation request. To ask for permission to use the webcam, use the CaptureDeviceConfiguration.RequestDeviceAccess( ) method. Make this call and you will the following dialog.

Once the user has granted permission you can grab the video stream with a few lines of code.

CaptureSource cs;

var device = CaptureDeviceConfiguration.GetDefaultVideoCaptureDevice();
if (null != device)
{
   cs = new CaptureSource();
   cs.VideoCaptureDevice device vcd;
   cs.Start();

   var brush = new VideoBrush();
   brush.Stretch = Stretch.Uniform;
   brush.SetSource(cs);
       rect.Fill = videoBrush;
}

Trusted applications

Additional features are available to OOB applications which are granted trust from the user. Simply set the "Require elevated trust…" checkbox in the Visual Studio 2010 properties settings. Yes, Silverlight has a group policy which administrators can use to manage which applications or domains are trusted.

The user will see the following dialog box when converting a Silverlight application to an OOP application.

Now that you have full trust, here is a partial list of the new Silverlight 4 privileges.

• Full Screen Keyboard Access: To prevent spoofing attacks Silverlight 3 disables most keyboard events while in full screen mode. In Silverlight 4 this restriction has been lifted for trusted OOB applications.
• File Access: Read and write to the more areas of the hard drive including My Music, My Document etc. on Windows OS and similar location on the Mac.
• COM automation: Permits access to COM automation servers like Microsoft Excel, USB security card readers and other devices.
• Network Cross Domain: Networking restrictions on HTTP access are dropped for trusted OOB applications. Grab resources from any domain without needing a cross-domain policy file in place.

[Original article on TechTarget.com]

This question crops up from time to time. “Why is my Silverlight Usercontrol background always White?”.

Take this simple example.

<UserControl x:Class="Blog.WpfWonderland.MainPage"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         Background='Orange'>
    <Grid x:Name="LayoutRoot">

    </Grid>
</UserControl>

Run this example and you get a white page.  To be more precise you will get a page that is the color specified in the host page.   Change the color of the background in the host page object tag as shown below and you will see a green page.  Still no orange colored UserControl.

<object data="data:application/x-silverlight-2," 

        type="application/x-silverlight-2"
        width="100%" height="100%">
        <param name="background" value="green" />

The solution is simple as seen below.

<!– The solution.

   Assign the background brush to a top level
    Panel that is set to
   be the same size as the parent UserControl-->
<Grid x:Name="LayoutRoot"
      Background='Orange'>
       <!-- put the rest of your UI in another panel -->
    <Grid Width='200'
                Height='300' 

Background='Yellow'>

    </Grid>
    </Grid>