Michael Washington (ADefWebserver)

DotNetNuke® Silverlight Traffic Module

webmaster@openlightgroup.net — Sun, 07 Mar 2010 19:50:47 GMT

At the last Microsoft MVP summit, I was eating lunch with Jeff Paries who I had collaborated with on previous Silverlight projects, but had not met in person until that week. I commented that I had not used the Silverlight gauge he created about a year ago because it was too big...

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Yet Another Silverlight File Uploader

webmaster@openlightgroup.net — Sun, 21 Feb 2010 02:16:48 GMT

You are probably thinking “Didn’t he already post a free DotNetNuke Silverlight file Uploader ?”. Well yeah I did, but this one is different.

This one allows a DotNetNuke portal administrator to place an instance of the module on a page and upload files. Each file has the ModuleID saved in its database record. The module will only show files for that module instance.

Each module instance has it’s own set of files, so you can set different visibility and permissions. It uses a Silverlight upload control so you can upload large files and select multiple files to be uploaded at one time.

You can download the module and the source at this link.

Silverlight Keep Logged In: Prevent pages from timing out

webmaster@openlightgroup.net — Fri, 12 Feb 2010 14:51:08 GMT

If you have a page that contains a lot of information for users to enter, you can run into a problem where their authentication will “time out”. Usually this authentication is set to expire after 20 minutes of “inactivity” (the user has not submitted a request to the web server). The problem is that if they, for example, click the Save button after their authentication has expired, their content is not saved and they are logged out of the site instead.

To prevent this, you can install the Silverlight Keep Logged In module. When you place it on a page, there is no UI just a Title.

You can go into Settings for the module and change them so that nothing appears at all on the page but the module will still work.

Note, it has to be set so that Registered Users have View Module permission.

Any page that the module is on will not “time out” for the user. The module works by making a “call” to a web service in the website every 10 minutes. It uses a hidden Silverlight application to do this.

Silverlight runs in the “context of the user’s web browser”, so if the user is logged in, the Silverlight application running on the web page is “logged in”. When it makes a request of the website, the website detects that the user is making a request and it refreshes the the users “authentication token”.

The Problem

When a DotNetNuke module displays it’s first page, or it’s “default page”, all other modules on the page are also displayed. If the Silverlight Keep Logged In module is on the page, the user will not “time out”. However, if any other page in a module is displayed, all other modules are not displayed. In this case, the Silverlight Keep Logged In module will not work.

In this case, it would be necessary to incorporate the Silverlight Keep Logged In module code into the code of the custom module. The module structure is simple:

There is a View.ascx control to launch the hidden Silverlight application (SilverlightKeepLoggedIn.xap), with a supporting Silverlight.js file. There is also a web service that contains this code:

<%@ WebService Language="C#" Class="SilverlightKeepLoggedIn.WebService" %>
using System.Web.Services;
using DotNetNuke.Entities.Users;
namespace SilverlightKeepLoggedIn
{
    [WebService(Namespace = "http://ADefWebserver.com/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    public class WebService : System.Web.Services.WebService
    {
        [WebMethod]
        public void KeepAlive()
        {
            // Calling this web method keeps the user active
        }
    }
}

The Silverlight application uses the following code:

using System;
using System.Windows.Controls;
using SilverlightKeepLoggedIn.wsKeepLoggedIn;
using System.ServiceModel;
namespace SilverlightKeepLoggedIn
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            // Set up timer
            System.Windows.Threading.DispatcherTimer dt = 
                new System.Windows.Threading.DispatcherTimer();
            // Set to call every 10 minutes
            dt.Interval = new TimeSpan(0, 0, 10, 0, 0);
            // Set up event handler
            dt.Tick += new EventHandler(dt_Tick);
            // Start timer
            dt.Start();
        }
        void dt_Tick(object sender, EventArgs e)
        {
            // Call web service
            CallWebService();
        }
        private string GetWebserviceAddress()
        {
            string strXapFile = @"/ClientBin/SilverlightKeepLoggedIn.xap";
            string strBaseWebAddress = 
                App.Current.Host.Source.AbsoluteUri.Replace(strXapFile, "");
            return string.Format(@"{0}/{1}", strBaseWebAddress, "WebService.asmx");
        }
        private void CallWebService()
        {
            // Set up web service call
            WebServiceSoapClient objWebServiceSoapClient = 
                new WebServiceSoapClient();
            EndpointAddress MyEndpointAddress = new 
                EndpointAddress(GetWebserviceAddress());
            objWebServiceSoapClient.Endpoint.Address = MyEndpointAddress;
            // Call web method
            objWebServiceSoapClient.KeepAliveAsync();
        }
    }
}

Download the DotNetNuke module

You can download the DotNetNuke 4+ module at this link.

Easy Simple Unit umm Business Rule Testing (for DotNetNuke and Linq to SQL)

webmaster@openlightgroup.net — Sun, 07 Feb 2010 00:34:29 GMT

At my day job we have an advanced developer who was given a difficult project where he has to implement a dozen business rules. I’m talking “ask for a blessing before you go in” and “ask for forgiveness when you come out” complicated code.

I watched him work on the code, and he is methodical at writing down the rules and writing a test case to make sure he properly implemented it. This usually involves creating a “test case” by setting up data in the database just right and then clicking buttons and links and checking the expected output. I have worked with him over a year, and I can assure you he has probably deleted more good code than I have ever written. Everything is properly structured and segmented and the overall design will bring tears to you eyes with the beauty of it’s implementation.

But management keeps asking for major changes.

So I see this developer re-think his design and carefully re-factor his code to accommodate huge changes in requirements. He carefully retests all the existing business rules as he implements the new ones. Sometimes it takes hours for him to properly test everything. The guy is a total pro and he gets the job done.

But, here is the problem. He is a contract programmer, and when he moves on to his next job guess who has to maintain the code… me!

I had a nightmare where management came up to me and they wanted to “enhance” that code “one more time”. How can I make management understand that it could take me 6 hours to make just one small change to the code? Yes the code is well designed but it simply cannot anticipate all the requirements that are being demanded of it. It constantly has to be re-factored and each re-factoring brings a very real risk of breaking existing code.

Unit Testing

I am sure we have all read blogs on “getting started with unit testing”. They show a simple test that calls a method that returns some prime number. First the test fails because the code has not been written, next, they write the code and the test passes. “Wow this is great” you say, and then look for some examples where they connect to the database.

Now you are wading through a lot of complicated examples to Initialize() and Cleanup() to get the data just right. You are actually spending considerable time to “set-up a valid test” and then return the data to the previous state so the test is repeatable. When you realize that there is more code to “properly Unit Test” than there is in the project it’s self you come to the conclusion that it is not worth it. Just fix the bugs as they come, it will take less time.

However, in this case I needed Unit Tests to manage the complexity of the business rules. I really don’t care about “proper code coverage” and “proper isolation”, I just want something to help me so I don’t lie awake at 2:00 am thinking about accidently breaking some very important code.

Easy Unit Business Rule Testing

There is wonderful stuff out there on Unit Testing but I needed something simple and easy. A Unit Test purist would pass out from shock at the manner I butcher the normal Unit Testing paradigm.

The main thing I did was only test the specific methods I cared about, and only for business rule adherence. I load up a bunch of sample data and then toss it into a business object and check the expected result. Since I am using Linq to SQL, it is easy to implement the ‘Repository Pattern” and substitute my sample tables for real ones. The code doesn’t realize that it is not connecting to a real database and produces the same output for the same input every time.

But understand, when others talk about Unit testing, this is not what they mean. You should be testing each method inside the business object. If all tests pass you then know that the any re-factoring “should” not have broken anything.

This is Unit Testing for the guy who buys Life Insurance only if he plans to travel. I just call the methods on the “outside” of the business object and ask for an expected result. If I need to, I can test specific methods “on the inside” (methods that are called by the primary methods).

So it isn’t really Unit Testing, I guess it’s “Business Rule Testing”.

You can read the article here:

http://www.adefwebserver.com/DotNetNukeHELP/Misc/UnitTesting/

ADefSignUp: Email Sign-Up and Verification Module

webmaster@openlightgroup.net — Wed, 03 Feb 2010 14:44:52 GMT

I just posted a module that allows you to easily create a sign-up list of verified email addresses.

A DotNetNuke portal administrator can place an instance of the module on a page and customize the sign-up message and the email verification message. The captured data can also be exported to Excel.

The module and code are posted here:

http://www.adefwebserver.com/DotNetNukeHELP/Misc/SignUp/

DotNetNuke 5 Hello World II (Using a Database)

webmaster@openlightgroup.net — Sun, 17 Jan 2010 19:27:16 GMT

How to make a simple Module using DotNetNuke 5 that connects to the Database

Use the following tutorial to create a simple Hello World DotNetNuke 5 Module. it will be used as the starting point for this tutorial:

DotNetNuke 5 Hello World

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DotNetNuke 5 Hello World

webmaster@openlightgroup.net — Sun, 17 Jan 2010 15:01:45 GMT

How to make a simple Hello World Module using DotNetNuke 5...

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Silverlight Message Board using the CloudDB.com “cloud” database

webmaster@openlightgroup.net — Sat, 09 Jan 2010 22:47:51 GMT

Click here for the live example:

http://www.adefwebserver.com/silverlight/CloudDBSilverlight/Default.aspx

I checked Twitter yesterday and saw a post about CloudDB.com giving away free invites...

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Closed Captioning with Silverlight (using MVVM)

webmaster@openlightgroup.net — Sat, 02 Jan 2010 18:03:25 GMT

Live example: http://www.adefwebserver.com/silverlight/SilverlightCaptioning/SilverlightDynamicMediaMarkers/

This is another one of my “this blog post is not really about what this blog post is about”. Yes, I will deliver on what the title promises, but creating closed captaining with Silverlight is actually very easy. The thing that took me so much time to put together, was implementing a “MVVM like” pattern and have a code behind that has no application logic and looks like this:

using System.Windows.Controls;
namespace SilverlightDynamicMediaMarkers
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
       }
    }
}

From what I understand, it means that each layer is de-coupled and independently testable. When you change a caption and restart the video, it picks up the changes through bindings to dependency properties that are automatically updated.

But, first…

Creating Closed Captioning with Silverlight 3.0

The Silverlight 3 MediaElement allows you to create a collection of TimelineMarkers like this:

TimelineMarker objTimelineMarker1 = new TimelineMarker();
objTimelineMarker1.Text = Caption1;
objTimelineMarker1.Time = new TimeSpan(0, 0, 5);
objTimelineMarker1.Type = "Start";
TimelineMarker objTimelineMarker2 = new TimelineMarker();
objTimelineMarker2.Text = "";
objTimelineMarker2.Time = new TimeSpan(0, 0, 10);
objTimelineMarker2.Type = "Stop";
TimelineMarkerCollection colTimelineMarkerCollection =
    new TimelineMarkerCollection();
colTimelineMarkerCollection.Add(objTimelineMarker1);
colTimelineMarkerCollection.Add(objTimelineMarker2);

And attach them to the media like this:

public void UpdateTimelineMarkers()
{
    // Clear existing Markers
    this.media.Markers.Clear();
    if (MediaTimelineMarkerCollection != null)
    {
        // Add Markers
        foreach (var Marker in MediaTimelineMarkerCollection)
        {
            TimelineMarker objTimelineMarker = new TimelineMarker();
            objTimelineMarker.Text = Marker.Text;
            objTimelineMarker.Time = Marker.Time;
            objTimelineMarker.Type = Marker.Type;
            this.media.Markers.Add(objTimelineMarker);
        }
    }
}

As the media is playing (this can be a video or even a Mp3 file) the MarkerReached Event will fire, passing an instance of the marker as an argument. It can then be used to display subtitles in a text box that is overlain on top of the video.

private void media_MarkerReached(object sender, 
    TimelineMarkerRoutedEventArgs e)
{
    ClosedCaption.Visibility = (e.Marker.Type == "Start") 
        ? Visibility.Visible : 
        Visibility.Collapsed;
    ClosedCaption.Text = e.Marker.Text.ToString();
}

Note, that you could use the media markers for a lot of other things such as triggering a JavaScript method on the hosting .html page that causes other things on the page to change.

You can also create media markers and embed them in the media using a product such as Microsoft Expression Blend.

The Closed Captioning Program

Implementing closed captaining will take you about 5 minutes. However, my desire was to create a program that would allow you to enter captions on the fly and when you re-start the video, you would see them. Note, you have to stop, rewind a bit, and restart the video to get new captions to show up. You hover over the video to get the play control to show so you can stop the video.

I could have simply put a button on the page that would reload the video, but I wanted to use bindings to tie everything together in a “MVVM like” architecture

I say “MVVM like” because it is hard to get two people to agree on what MVVM is in Silverlight means because apparently Silverlight 3 does not allow “true MVVM” because it is missing things like commanding and triggers. There are frameworks available that get past these limitations.

The Captions

First, I created 3 TextBoxes to hold the Captions.

I set bindings on each of the controls:

<TextBox x:Name="txtCaption1" Grid.Column="2" Grid.Row="1" 
Text="{Binding Caption1, Mode=TwoWay, UpdateSourceTrigger=Default}" 
TextWrapping="Wrap"/>

The bindings work because I set a DataContext on the Parent object that they are contained in, to a class called ViewModel:

xmlns:local="clr-namespace:SilverlightDynamicMediaMarkers">
<Canvas x:Name="LayoutRoot">
<Canvas.DataContext>
  <local:ViewModel />
Canvas.DataContext>

In the ViewModel class I created a ObservableCollection of TimeLineMarkers property and set the TimelineMarkers property to rebuild each time one of the captions is changed. This happens because the binding is set to TwoWay and the ViewModel class implements the INotifyPropertyChanged interface and the Caption properties trigger NotifyPropertyChanged.

#region Caption1
public string Caption1
{
    get
    {
        return this._Caption1;
    }
    set
    {
        if (value != this._Caption1)
        {
            this._Caption1 = value;
            NotifyPropertyChanged("Caption1");
            TimelineMarkers = BuildTimelineMarkers();
        }
    }
}
#endregion

The Video Player

The Blacklight Codeplex project has a great set of controls with full source code. I took the video player from that project and added a TextBlock over the video player to display the captions.

I now have a ViewModel class that is bound to the user interface. When you change a caption and move focus from the TextBox, the TimelineMarkers property will be rebuilt. You can set a break point in the code and see this for yourself.

Now, I need to bind the video player in the MediaPlayer control to the collection of TimelineMarkers in ViewModel. To do this, I created dependency property.

The UpdateTimelineMarkers() method in the MediaPlayer control, (listed above) gets the TimelineMarkers from the collection contained in the MediaTimelineMarkers property of the MediaPlayer control. Here is the code for that property:

public ObservableCollection MediaTimelineMarkerCollection
{
    get 
    { 
        return 
        (ObservableCollection)GetValue(MediaTimelineMarkerProperty); 
    }
    set { SetValue(MediaTimelineMarkerProperty, value); }
}

This property reads and sets the MediaTimelineMarkerProperty dependency property. here is the declaration for that property:

public static readonly DependencyProperty MediaTimelineMarkerProperty =
    DependencyProperty.Register("MediaTimelineMarkerCollection", 
    typeof(ObservableCollection), typeof(MediaPlayer), 
    new PropertyMetadata(new PropertyChangedCallback(MediaTimelineMarker_Changed)));

This declaration contains a pointer to MediaTimelineMarker_Changed that will fire whenever it is changed. Here is the code for that method:

private static void MediaTimelineMarker_Changed(DependencyObject 
    dependencyObject, DependencyPropertyChangedEventArgs eventArgs)
{
    MediaPlayer mediaPlayer = (MediaPlayer)dependencyObject;            
    mediaPlayer.MediaTimelineMarkerCollection = 
        (ObservableCollection)eventArgs.NewValue;
}

This allows us to bind the TimelineMarkers collection in ViewModel, to the MediaTimelineMarkerCollection in the MediaPlayer control, by using simple binding code (in MainPage.xaml) like this:

<controls:MediaPlayer x:Name="myMediaPlayer" 
MediaTimelineMarkerCollection="{Binding TimelineMarkers, Mode=TwoWay, UpdateSourceTrigger=Default}" 
MediaSource="Media/niceday.wmv"
Canvas.Left="27" Canvas.Top="32" Height="248" Width="365" />

MVVM The good and the Bad

A lot of time was lost in creating this program when I had a typo in my Dependency property declaration. Also, when you make a mistake with a binding in XAML you wont always get a compile-time error, you will get a run-time error.

However, consuming the video player and binding to it’s properties using declarative binding and collections that automatically update does require less code.

Download the code here:

http://www.adefwebserver.com/silverlight/SilverlightCaptioning/SilverlightDynamicMediaMarkers.zip

Crossing Silverlight Objects

webmaster@openlightgroup.net — Sun, 27 Dec 2009 15:51:26 GMT

Live Example: http://www.adefwebserver.com/silverlight/SilverlightOrb/SilverlightOrbv1/

This is actually a failed experiment. The theory was that XAMl contains all the visual elements you need to “cross” two Silverlight objects to create child objects that resemble the parents.

However, a failed experiment is no reason to let code go to waste!

Along the way I learned some things:

How to display XAML elements in a drop down
How to zoom in on elements using a Viewbox and a ScrollViewer

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