The Silverlight-Plugin runs per default on Windows and MacOs. For Linux-Machines there’s an opensource implementation driven by Microsoft and Novell called Moonlight. While Silverlight is currently in Version 3 available and Version 4 (already in beta) is expected for spring next year, the Moonlight implementation was only availabe in Version 1. And Version 1 means no C#, no CLR, just hacking JavaScript and XAML. But two days ago the big step for Silverlight on Linux was done and Moonlight reached version 2. It’s available for download: http://www.mono-project.com/Moonlight I think with reaching that level from “only-JavaScript” to the managed C#-API, the future releases of Moonlight will be more closely to the Silverlight-releases for Windows.

Focusing a TextBox that’s inside a Custom Control isn’t so easy at startup of your application. Let me explain the problem that is also discussed on http://forums.silverlight.net/forums/t/151235.aspx. Imagine you’ve created a custom control that has a TextBox as Part-element. The Style that sets the Template would look like this:

<Style TargetType="local:SimpleControl">
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate  TargetType="local:SimpleControl">
        <Border Background="{TemplateBinding Background}"
          BorderBrush="{TemplateBinding BorderBrush}"
          BorderThickness="{TemplateBinding BorderThickness}">
          <TextBox x:Name="PART_Text" Margin="10"></TextBox>
        </Border>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

You get the TextBox from the Template in the OnApplyTemplate-Method

public override void OnApplyTemplate()
{
  base.OnApplyTemplate();
  _partTextBox = this.GetTemplateChild("PART_Text") as TextBox;
}

Now imaginge you want to focus your SimpleControl in the constructor of your MainPage like below:

public MainPage()
{
  InitializeComponent();
  HtmlPage.Plugin.Focus();
  yourControl.Focus();
}

The Problem that occurs is that the OnApplyTemplate-Method is called after the Focus-Method. So you don’t have the TextBox defined in your Template. The Solution is very easy. Just hide the Focus-Method from the base-class and set a flag. But keep in mind that this won’t work if you store your SimpleControl in a variable of type Control, cause then no polymorphic call is made to the Focus-Method defined in SimpleControl. Here a sample implementation:

public class SimpleControl : Control
{
  private bool _applyFocusToPartTextBox;
  private TextBox _partTextBox;
  public SimpleControl()
  {
    this.DefaultStyleKey = typeof(SimpleControl);
  }
  public override void OnApplyTemplate()
  {
    base.OnApplyTemplate();
    _partTextBox = this.GetTemplateChild("PART_Text") as TextBox;
    if (_partTextBox != null)
    {
      if (_applyFocusToPartTextBox)
        _partTextBox.Focus();
    }
    _applyFocusToPartTextBox = false;
  }
  public new bool Focus()
  {
    if (_partTextBox == null)
    {
      _applyFocusToPartTextBox = true;
      return true;
    }
    return base.Focus();
  }
}

On www.silverlight.net several people are asking how to print the values of a DataGrid in Silverlight. You cannot just assign the DataGrid to the PageVisual-Property of the PrintPageEventArgs. This would just print the DataGrid as it is on one page. The data wouldn’t be splitted on several pages, cause there’s no paging logic to use. You’ve to write this logic. You’re responsible for the paging! But how to do it? In this post I’ll give you a little idea how it could work by simple printing out a List of string-values. I won’t talk a lot about the details. Just look at the code below:

public partial class MainPage : UserControl
{
  private List _list;
  private const double ROWHEIGHT = 20;
  private const double PAGEMARGIN = 30;
  public MainPage()
  {
    InitializeComponent();
    _list = new List();

    for (int i = 1; i < 101; i++)
    {
      _list.Add(i + " thanks to Thomas for this printing sample");
      _list.Add("Visit http://www.thomasclaudiushuber.com");
    }
  }

  private void Button_Click(object sender, RoutedEventArgs e)
  {
    _currentIndex = 0;

    var pd = new PrintDocument();
    pd.DocumentName = "AListFromThomas";
    pd.PrintPage += pd_PrintPage;
    pd.Print();

  }

  private int _currentIndex;
  private double _currentTop;
  private double _availableSpace;
  void pd_PrintPage(object sender, PrintPageEventArgs e)
  {
    var pageRoot = new Canvas();
    e.PageVisual = pageRoot;

    _currentTop = PAGEMARGIN;
    _availableSpace = e.PrintableArea.Height - PAGEMARGIN*2;
    while (_currentIndex < _list.Count)
    {
      var txt = new TextBlock { Text = _list[_currentIndex] };

      if (ROWHEIGHT > _availableSpace)
      {
        e.HasMorePages = true;
        break;
      }

      txt.SetValue(Canvas.TopProperty, _currentTop);
      txt.SetValue(Canvas.LeftProperty, PAGEMARGIN);
      pageRoot.Children.Add(txt);
      _currentTop += ROWHEIGHT;
      _availableSpace -= ROWHEIGHT;
      _currentIndex++;
    }
  }
}

When the Button_Click-Eventhandler is executed, the List gets printed over 5 pages. You can easily print it to PDFCreator or XPS Printer to test it. The output looks like this: Download the source here and enjoy. Give me feedback by entering a comment to this blogentry or via email on www.thomasclaudiushuber.com/blog.

You can restrict the input-values in Silverlight’s TextBox by handling the KeyDown-Event. But the KeyDown-Event isn’t fired if the user enters a key by pressing e.g. ALT + 123. Corresponding to the problem mentioned in http://forums.silverlight.net/forums/t/147718.aspx, I’ll show here a short workaround by using the TextChanged and KeyUp-Event of the TextBox. Just use the following snippet, that removes a character that was added by pressing the ALT- and another Key or Key-Combination:

private void TextBox_TextChanged(object sender, TextCh… e)
{
  if (_altWasPressed)
  {
    // remove the added character
    var textBox = ((TextBox)sender);
    var caretPos = textBox.SelectionStart;
    var text = textBox.Text;
    var textStart = text.Substring(0, caretPos - 1);
    var textEnd = "";
    if (caretPos < text.Length)
      textEnd = text.Substring(caretPos, text.Length-caretPos);
    textBox.Text = textStart + textEnd;
    textBox.SelectionStart = caretPos - 1;

    _altWasPressed = false;
  }
}
private bool _altWasPressed;
private void TextBox_KeyUp(object sender, KeyEventArgs e)
{
  _altWasPressed = e.Key == Key.Alt;
}

… my expectations about a Major 4.0 release next year may come true: Silverlight 4.0, WPF 4.0, .NET 4.0, Expression Blend 4.0 etc. Today Microsoft announced Silverlight 4.0 Beta 1 available for download. There are impressing features for business applications like print support, clipboard, Drag’n’Drop or local fileaccess through full trusted Silverlight-Applications. I’m glad the Galileo-Computing team and I decided to publish my upcoming Silverlight-book to version 4.0. More infos about the book soon here: www.thomasclaudiushuber.com/silverlight. Find all interesting links about the Beta 1 of Silverlight 4.0 on the site below: http://www.silverlight.net/getstarted/silverlight-4-beta/ Cheers Thomas

Thanks to all who visited my Session about building datadriven Business-Applications with Silverlight 3 yesterday at the PrioConference in Munich. I hope you enjoyed it. You can download the Slides here. To get the Live-Demos, please contact me directly via the contact-Form of my homepage and I’ll send them to you. Yesterday in the evening there was a coding-dojo about the KataPotter-Problem. If you attended the next lines of this post may be interesting for you. With the knowledge of the 2,2,2,1,1-Problem I solved the problem from “zero to hero” today while sitting in the train from Munich to Basel in about 45 Minutes. Really 45 Minutes, even a bit less. The idea to solve the problem has already been in my mind yesterday. Because of that  I couldn’t hardly believe Ralf “Dr. Clean Code” Westphal when he and his colleague Stefan said it would need 4 hours to implement the algorithm. Maybe four hours for santaclaus, but not for me. ;-) I think they exaggerated a little bit with the four hours, because it was already half past ten and everybody was thirsty... Download my 45-Minutes-not-Refactored-Algorithm (sorry for the method with more than ten lines ;-)) here. What about your algorithms? How did you solve the problem? Are there more tests for my Application that won’t work like the customer would expect? Any comments and hints are welcome. So, finally, another PrioConference is over. I enjoyed it, it was a really great event. Thanks to Dagmar, Ralph, Tilman, dotnetpro & Co. and all people behind the scences for the great organization and professionality.