ContentControl and static ressources - xaml

Question

I try to extend my app with the missing CharacterEllipsis for TextBlocks in my Windows Phone 8 app. I found a nice solution here: http://nerdplusart.com/texttrimming-textblock-for-silverlight/.
So I implemented this in my code:
public class DynamicTextBlock : ContentControl
{
#region Text (DependencyProperty)
/// <summary>
/// Gets or sets the Text DependencyProperty. This is the text that will be displayed.
/// </summary>
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(DynamicTextBlock),
new PropertyMetadata(null, new PropertyChangedCallback(OnTextChanged)));
private static void OnTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((DynamicTextBlock)d).OnTextChanged(e);
}
protected virtual void OnTextChanged(DependencyPropertyChangedEventArgs e)
{
this.InvalidateMeasure();
}
#endregion
#region TextWrapping (DependencyProperty)
/// <summary>
/// Gets or sets the TextWrapping property. This corresponds to TextBlock.TextWrapping.
/// </summary>
public TextWrapping TextWrapping
{
get { return (TextWrapping)GetValue(TextWrappingProperty); }
set { SetValue(TextWrappingProperty, value); }
}
public static readonly DependencyProperty TextWrappingProperty =
DependencyProperty.Register("TextWrapping", typeof(TextWrapping), typeof(DynamicTextBlock),
new PropertyMetadata(TextWrapping.NoWrap, new PropertyChangedCallback(OnTextWrappingChanged)));
private static void OnTextWrappingChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((DynamicTextBlock)d).OnTextWrappingChanged(e);
}
protected virtual void OnTextWrappingChanged(DependencyPropertyChangedEventArgs e)
{
this.textBlock.TextWrapping = (TextWrapping)e.NewValue;
this.InvalidateMeasure();
}
#endregion
#region LineHeight (DependencyProperty)
/// <summary>
/// Gets or sets the LineHeight property. This property corresponds to TextBlock.LineHeight;
/// </summary>
public double LineHeight
{
get { return (double)GetValue(LineHeightProperty); }
set { SetValue(LineHeightProperty, value); }
}
public static readonly DependencyProperty LineHeightProperty =
DependencyProperty.Register("LineHeight", typeof(double), typeof(DynamicTextBlock),
new PropertyMetadata(0.0, new PropertyChangedCallback(OnLineHeightChanged)));
private static void OnLineHeightChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((DynamicTextBlock)d).OnLineHeightChanged(e);
}
protected virtual void OnLineHeightChanged(DependencyPropertyChangedEventArgs e)
{
textBlock.LineHeight = LineHeight;
this.InvalidateMeasure();
}
#endregion
#region LineStackingStrategy (DependencyProperty)
/// <summary>
/// Gets or sets the LineStackingStrategy DependencyProperty. This corresponds to TextBlock.LineStackingStrategy.
/// </summary>
public LineStackingStrategy LineStackingStrategy
{
get { return (LineStackingStrategy)GetValue(LineStackingStrategyProperty); }
set { SetValue(LineStackingStrategyProperty, value); }
}
public static readonly DependencyProperty LineStackingStrategyProperty =
DependencyProperty.Register("LineStackingStrategy", typeof(LineStackingStrategy), typeof(DynamicTextBlock),
new PropertyMetadata(LineStackingStrategy.BlockLineHeight, new PropertyChangedCallback(OnLineStackingStrategyChanged)));
private static void OnLineStackingStrategyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((DynamicTextBlock)d).OnLineStackingStrategyChanged(e);
}
protected virtual void OnLineStackingStrategyChanged(DependencyPropertyChangedEventArgs e)
{
this.textBlock.LineStackingStrategy = (LineStackingStrategy)e.NewValue;
this.InvalidateMeasure();
}
#endregion
/// <summary>
/// A TextBlock that gets set as the control's content and is ultiately the control
/// that displays our text
/// </summary>
private TextBlock textBlock;
/// <summary>
/// Initializes a new instance of the DynamicTextBlock class
/// </summary>
public DynamicTextBlock()
{
// create our textBlock and initialize
this.textBlock = new TextBlock();
this.Content = this.textBlock;
}
/// <summary>
/// Handles the measure part of the measure and arrange layout process. During this process
/// we measure the textBlock that we've created as content with increasingly smaller amounts
/// of text until we find text that fits.
/// </summary>
/// <param name="availableSize">the available size</param>
/// <returns>the base implementation of Measure</returns>
protected override Size MeasureOverride(Size availableSize)
{
// just to make the code easier to read
bool wrapping = this.TextWrapping == TextWrapping.Wrap;
Size unboundSize = wrapping ? new Size(availableSize.Width, double.PositiveInfinity) : new Size(double.PositiveInfinity, availableSize.Height);
string reducedText = this.Text;
// set the text and measure it to see if it fits without alteration
this.textBlock.Text = reducedText;
Size textSize = base.MeasureOverride(unboundSize);
while (wrapping ? textSize.Height > availableSize.Height : textSize.Width > availableSize.Width)
{
int prevLength = reducedText.Length;
reducedText = this.ReduceText(reducedText);
if (reducedText.Length == prevLength)
{
break;
}
this.textBlock.Text = reducedText + "...";
textSize = base.MeasureOverride(unboundSize);
}
return base.MeasureOverride(availableSize);
}
/// <summary>
/// Reduces the length of the text. Derived classes can override this to use different techniques
/// for reducing the text length.
/// </summary>
/// <param name="text">the original text</param>
/// <returns>the reduced length text</returns>
protected virtual string ReduceText(string text)
{
return text.Substring(0, text.Length - 1);
}
}
And in my XAML I use this like this:
<myNamespace:DynamicTextBlock Grid.Column="0" Text="Dies ist ein Text der sehr lang ist und umebrochen wird" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="-1,0,0,0" Foreground="{Binding IsHighlighted, Converter={StaticResource BoolToBrushConverter}}" FontSize="32" />
Everything works cool. Now I want to apply a Style to this. But the following doesn´t work:
Style="{StaticResource PhoneTextLargeStyle}"
How the solution must be Extended to accept a StaticRessource as Style?

Answer 1

Styles in Windows Phone have a TargetType and they can only be set to controls of that type or its subtypes (child classes). PhoneTextLargeStyle's target is TextBlock, so you can't put it on other controls (like your DynamicTextBlock).
You would need to create a new style which targets DynamicTextBlock and sets the values that you like. I guess you can find out one way or another what the PhoneTextLargeStyle style does.