DependencyObject Binding
在Silverlight之前的版本中，其支持的元素绑定只是允许绑定继承自
FrameworkElement类下元素，但是比如一些形变比如
Transformations就不能绑定了。现在数据绑定也可以绑定继承自
DependencyObject下的任何元素。
==============================
<Grid x:Name="LayoutRoot"
Background="White">
<StackPanel Width="400" Margin="0,22,0,0">
<StackPanel.RenderTransform>
<CompositeTransform
ScaleX="{Binding Value,ElementName=stretcher}"
ScaleY="{Binding Value,ElementName=stretcher}" />
</StackPanel.RenderTransform>
<Button Content="Button"/>
<Button Content="Button"/>
<Button Content="Button"/>
<Button Content="Button"/>
<Button Content="Button"/>
</StackPanel>
<Slider Minimum=".5"
Maximum="4"
x:Name="stretcher"
Value="1" VerticalAlignment="Top" />
</Grid>
String Formatting
新版的Silverlight4中新增加了格式化字符串的能力。在这之前如果要做一个数据格式化不得不使用一个Converter来格式化字符串。现在可以使用扩展标记StringFormat来做一些比如日期、货币等的格式化。
在VS2010中也提供了可视化的支持。
=================================
<Grid x:Name="LayoutRoot" Background="White">
<TextBox Text="{Binding ReleaseDate, StringFormat='yyyy年MM月dd日',
Mode=TwoWay}"
Margin="0,30,0,0"
Height="26"
VerticalAlignment="Top" d:LayoutOverrides="Height" />
<TextBlock Text="{Binding Price, StringFormat='c'}"
Margin="0,0,0,0"
Height="26" VerticalAlignment="Top" />
</Grid>
=================================
Null and Fallback Values
在某些特殊的情况下，数据有可能加载失败。数据绑定中有新增加了两个宽展标记TargetNullValue、FallbackValue，TargetNullValue这个标记表示了当绑定值是null的时候显示的值。FallbackValue则是在数据未绑定时显示的值。
=================================
<Grid x:Name="LayoutRoot" Background="White">
<TextBlock Text="{Binding Developer,
TargetNullValue='(暂无)'}"
Height="26" Margin="0,100,0,0"
VerticalAlignment="Top" d:LayoutOverrides="Height" />
<TextBlock Text="{Binding Publisher,
FallbackValue='(暂无)'}" Height="26"
VerticalAlignment="Top" Margin="0,33,0,0" />
</Grid>
=================================
CollectionViewSource Changes
对于在GataGrid中做分组管理，现在的CollectionViewSource支持数据到GroupDescriptions的绑定，这样可以更加轻松的在XAML做分组。
=================================
<UserControl.Resources>
<CollectionViewSource x:Name="dataSource"
Source="{Binding}">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription PropertyName="Gender" />
<PropertyGroupDescription PropertyName="AgeGroup" />
</CollectionViewSource.GroupDescriptions>
<CollectionViewSource.SortDescriptions>
<compMod:SortDescription PropertyName="AgeGroup" Direction="Ascending"/>
</CollectionViewSource.SortDescriptions>
</CollectionViewSource>
</UserControl.Resources>
<Grid x:Name="LayoutRoot" Background="White">
<sdk:DataGrid ItemsSource="{Binding Source={StaticResource dataSource}}" />
</Grid>
=================================
=================================
代码
public
List
<
Person
>
GetPeople()
{
List
<
Person
>
peeps
=
new
List
<
Person
>
();
peeps.Add(
new
Person() { FirstName
=
"
Wang
"
, LastName
=
"
Zhe
"
, Gender
=
"
M
"
, AgeGroup
=
"
Adult
"
});
peeps.Add(
new
Person() { FirstName
=
"
nasa
"
, LastName
=
"
wang
"
, Gender
=
"
M
"
, AgeGroup
=
"
Adult
"
});
peeps.Add(
new
Person() { FirstName
=
"
summer
"
, LastName
=
"
liang
"
, Gender
=
"
F
"
, AgeGroup
=
"
Kid
"
});
peeps.Add(
new
Person() { FirstName
=
"
liang
"
, LastName
=
"
jing
"
, Gender
=
"
F
"
, AgeGroup
=
"
Kid
"
});
return
peeps;
}
=================================
Error Propogation
Silverlight的数据验证机制，在这里得到了很多的扩充，提供了IDataErrorInfo、INotifyDataErrorInfo从而能得到更多的信息。
