上文说到，WinRt中，我们不能在Style的Setter使用Binding.这个问题其实从SL5之前，一直都不可以。但是，为了使用强大的Binding,人们也一直想使用各种方法来达到Binding
从茫茫的Web里找一个有用的东西，本来是很简单的一件事，但是，MS最近几年，经常自我革新，革自己的命，经常今天可以用的技术，明天换个名字，少点东西，就出来让万千小白来试了。从WPF/SL/WinRT一样的Xaml却不一样的精彩。我们常常想，要是WinRT的Xmal也如WPF的那么强大就好了。但这也是只是想想而已。
言归正传
在SL时代，我们参看的一般是这一文章
在WinRT时代，我们借助于SO，找到这个
WinRT : Simple ScheduleControl
另外还一个C++/DX用的
WinRT and C++/CX compatible way to set Bindings via Styles
在这里我们找到一直以来想要的一个帮助类SetterValueBindingHelper.
如下：
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Reflection;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Markup; namespace SLWeek.Utils
{
[ContentProperty(Name = "Values")]
public class SetterValueBindingHelper
{
/// <summary>
/// Optional type parameter used to specify the type of an attached
/// DependencyProperty as an assembly-qualified name, full name, or
/// short name.
/// </summary>
[SuppressMessage("Microsoft.Naming", "CA1721:PropertyNamesShouldNotMatchGetMethods",
Justification = "Unambiguous in XAML.")]
public string Type { get; set; } /// <summary>
/// Property name for the normal/attached DependencyProperty on which
/// to set the Binding.
/// </summary>
public string Property { get; set; } /// <summary>
/// Binding to set on the specified property.
/// </summary>
public Binding Binding { get; set; } /// <summary>
/// Collection of SetterValueBindingHelper instances to apply to the
/// target element.
/// </summary>
/// <remarks>
/// Used when multiple Bindings need to be applied to the same element.
/// </remarks>
public Collection<SetterValueBindingHelper> Values
{
get
{
// Defer creating collection until needed
if (null == _values)
{
_values = new Collection<SetterValueBindingHelper>();
}
return _values;
}
} private Collection<SetterValueBindingHelper> _values; /// <summary>
/// Gets the value of the PropertyBinding attached DependencyProperty.
/// </summary>
/// <param name="element">Element for which to get the property.</param>
/// <returns>Value of PropertyBinding attached DependencyProperty.</returns>
[SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters",
Justification = "SetBinding is only available on FrameworkElement.")]
public static SetterValueBindingHelper GetPropertyBinding(FrameworkElement element)
{
if (null == element)
{
throw new ArgumentNullException("element");
}
return (SetterValueBindingHelper)element.GetValue(PropertyBindingProperty);
} /// <summary>
/// Sets the value of the PropertyBinding attached DependencyProperty.
/// </summary>
/// <param name="element">Element on which to set the property.</param>
/// <param name="value">Value forPropertyBinding attached DependencyProperty.</param>
[SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters",
Justification = "SetBinding is only available on FrameworkElement.")]
public static void SetPropertyBinding(FrameworkElement element, SetterValueBindingHelper value)
{
if (null == element)
{
throw new ArgumentNullException("element");
}
element.SetValue(PropertyBindingProperty, value);
} /// <summary>
/// PropertyBinding attached DependencyProperty.
/// </summary>
public static readonly DependencyProperty PropertyBindingProperty =
DependencyProperty.RegisterAttached(
"PropertyBinding",
typeof(SetterValueBindingHelper),
typeof(SetterValueBindingHelper),
new PropertyMetadata(null, OnPropertyBindingPropertyChanged)); /// <summary>
/// Change handler for the PropertyBinding attached DependencyProperty.
/// </summary>
/// <param name="d">Object on which the property was changed.</param>
/// <param name="e">Property change arguments.</param>
private static void OnPropertyBindingPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
// Get/validate parameters
var element = (FrameworkElement)d;
var item = (SetterValueBindingHelper)(e.NewValue); if ((null == item.Values) || ( == item.Values.Count))
{
// No children; apply the relevant binding
ApplyBinding(element, item);
}
else
{
// Apply the bindings of each child
foreach (var child in item.Values)
{
if ((null != item.Property) || (null != item.Binding))
{
throw new ArgumentException(
"A SetterValueBindingHelper with Values may not have its Property or Binding set.");
}
if ( != child.Values.Count)
{
throw new ArgumentException(
"Values of a SetterValueBindingHelper may not have Values themselves.");
}
ApplyBinding(element, child);
}
}
} /// <summary>
/// Applies the Binding represented by the SetterValueBindingHelper.
/// </summary>
/// <param name="element">Element to apply the Binding to.</param>
/// <param name="item">SetterValueBindingHelper representing the Binding.</param>
private static void ApplyBinding(FrameworkElement element, SetterValueBindingHelper item)
{
if ((null == item.Property) || (null == item.Binding))
{
throw new ArgumentException(
"SetterValueBindingHelper's Property and Binding must both be set to non-null values.");
} // Get the type on which to set the Binding
Type type = null;
TypeInfo typeInfo = null;
if (null == item.Type)
{
// No type specified; setting for the specified element
type = element.GetType();
typeInfo = type.GetTypeInfo();
}
else
{
// Try to get the type from the type system
type = System.Type.GetType(item.Type);
if (null == type)
{
// Search for the type in the list of assemblies
foreach (var assembly in AssembliesToSearch)
{
// Match on short or full name
typeInfo = assembly.DefinedTypes
.Where(t => (t.FullName == item.Type) || (t.Name == item.Type))
.FirstOrDefault();
if (null != typeInfo)
{
// Found; done searching
break;
}
}
if (null == typeInfo)
{
// Unable to find the requested type anywhere
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture,
"Unable to access type \"{0}\". Try using an assembly qualified type name.",
item.Type));
}
}
else
{
typeInfo = type.GetTypeInfo();
}
} // Get the DependencyProperty for which to set the Binding
DependencyProperty property = null;
var field = typeInfo.GetDeclaredProperty(item.Property + "Property"); // type.GetRuntimeField(item.Property + "Property");
if (null != field)
{
property = field.GetValue(null) as DependencyProperty;
}
if (null == property)
{
// Unable to find the requsted property
throw new ArgumentException(string.Format(CultureInfo.CurrentCulture,
"Unable to access DependencyProperty \"{0}\" on type \"{1}\".",
item.Property, type.Name));
} // Set the specified Binding on the specified property
element.SetBinding(property, item.Binding);
} /// <summary>
/// Returns a stream of assemblies to search for the provided type name.
/// </summary>
private static IEnumerable<Assembly> AssembliesToSearch
{
get
{
// Start with the System.Windows assembly (home of all core controls)
yield return typeof(Windows.UI.Xaml.Controls.Control).GetTypeInfo().Assembly;
}
}
}
}
在这里我们要注册一点：
var field = typeInfo.GetDeclaredProperty(item.Property + "Property");
我们要清楚，依赖属性的问题，我们当前的typeInfo，他可能有的DeclaredProperty，很多是从基类继承过来的。所以，我们在使用的时候，在Xmal中设定SetterValueBindingHelper的Type是，一定要设定为基类。要不，就不能正常获得依赖属性
我们解决了Setter不能Binding的问题。
接下来，就完成间隔变色的问题
我们先要实现一个Conveter
public sealed class ListItemBackgroudConverter:IValueConverter
{
public SolidColorBrush OddColorBrush { get; set; }
public SolidColorBrush EvenColorBrush { get; set; }
public object Convert(object value, Type targetType, object parameter, string language)
{
var item = value as ListViewItem;
if (item != null)
{
var listView = ItemsControl.ItemsControlFromItemContainer(item);
if (listView != null)
{
var index = listView.IndexFromContainer(item);
return index % == ? EvenColorBrush : OddColorBrush;
}
} return null;
} public object ConvertBack(object value, Type targetType, object parameter, string language)
{
throw new NotImplementedException();
}
}
这个是我们的老套路了，为了方便在XMAL设定间隔色，我们定义了两种Brush
接下来，我们来定义Convetert和ListItem的ItemContainerStyle
<converter:ListItemBackgroudConverter x:Key="ListItemBackgroudConverter" OddColorBrush="{StaticResource SilverColorBrush}" EvenColorBrush="{StaticResource AsbestosColorBrush}"/><Style x:Key="ListItemBackgroud" TargetType="ListViewItem">
<Setter Property="utils:SetterValueBindingHelper.PropertyBinding">
<Setter.Value>
<utils:SetterValueBindingHelper Type="Control" Property="Background" Binding="{Binding RelativeSource={RelativeSource Self}, Converter={StaticResource ListItemBackgroudConverter}}"/>
</Setter.Value>
</Setter>
</Style>
再一次提醒注意，这里的Type是Control，而不是ListViewItem，因为只有Control的DeclaredProperty才有Backgroud.
我们在页面应用下这个Style
<ListView ItemsSource="{Binding ListPostTypes,Mode=TwoWay}" ItemContainerStyle="{StaticResource ListItemBackgroud}" Style="{StaticResource ListViewWrapItemsPanel}" ItemTemplate="{StaticResource SelectChannelTypeDataTemplate}"/>最后，我们看下效果：
由于我ListView的Style对ListView的容器进行了更改，换成了ItemsWrapGrid，所以，它会自动根据宽度进行排列
其Style为
<Style x:Key="ListViewWrapItemsPanel" TargetType="ListView">
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<ItemsWrapGrid Orientation="Horizontal"/>
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
</Style>