C# 4 and .NET 4

M a r k u p e x t e n s i o n s ❘ 741
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
MyAttachedPropertyProvider.SetMyProperty(button1, 44);
}
}
}
foreach (object item in LogicalTreeHelper.GetChildren(grid1))
{
FrameworkElement e = item as FrameworkElement;
if (e != null)
list1.Items.Add(String.Format(“{0}: {1}”, e.Name,
MyAttachedPropertyProvider.GetMyProperty(e)));
}
code snippet AttachedPropertyDemo/MainWindow.xaml.cs
There are some mechanisms available to extend classes at a later time. Extension
methods can be used to extend any class with methods. Extension methods only
support extending classes with methods, not properties. Extension methods are
explained in Chapter 3, “ Objects and Types. ” The ExpandoObject class allows the
extension of types with methods and properties. To use this feature, the class must
derive from ExpandoObject . ExpandoObject and dynamic types are explained in
Chapter 12, “ Dynamic Language Extensions. ”
Chapters 35 and 36 show many different attached properties in action, for example
attached properties from container controls such as Canvas , DockPanel , Grid , but also
the ErrorTemplate property from the Validation class.
marKuP eXTensions
With markup extensions you can extend XAML, with either element or attribute syntax. If an XML
attribute contains curly brackets, that ’ s a sign of a markup extension. Often markup extensions with
attributes are used as shorthand notation instead of using elements.
One example of such a markup extension is StaticResourceExtension , which fi nds resources. Here ’ s a
resource of a linear gradient brush with the key gradientBrush1 .
< Window.Resources >
< LinearGradientBrush x:Key="gradientBrush1" StartPoint="0.5,0.0" EndPoint="0.5, 1.0" >
< GradientStop Offset="0" Color="Yellow" / >
< GradientStop Offset="0.3" Color="Orange" / >
< GradientStop Offset="0.7" Color="Red" / >
< GradientStop Offset="1" Color="DarkRed" / >
< /LinearGradientBrush >
< /Window.Resources >
code snippet MarkupExtensionDemo/MainWindow.xaml
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