【windows phone】CollectionViewSource的妙用

在windows phone中绑定集合数据的时候，有时候需要分层数据，通常需要以主从试图形式显示。通常的方法是将第二个ListBox（主视图）的数据源绑定到第一个ListBox

（从视图）的SelectedItem，或者通过第一个ListBox的SelectionChanged事件来设置绑定。但是借助CollectionViewSource类可以更方便的实现；

CollectionView是一个集合视图类，支持数据的排序、分组、过滤。对数据的映像进行排列组合；

CollectionViewSource是CollectionView的一个XAML代理，可以在XAML中使用；

案例说明：用主从试图关系显示两个的员工列表；效果图如下：

前期工作，创建三个类来初始数据源；

（1）Employee.cs

    public class Employee
    {
        public int Number { get; set; } //工号
        public string  Name { get; set; } //姓名
        public string  Sex { get; set; } //性别
        public int BirthYear { get; set; } //出生年份
    }

（2）Department.cs

    public class Department:ObservableCollection<Employee>
    {
            public string DepName { get; set; }
            public ObservableCollection<Employee> Employees { get; set; }
    }

（3）DepartmentList.cs

    public class DepartmentList:ObservableCollection<Department>
    {
        public DepartmentList()
        {
            ObservableCollection<Employee> employee1 = new ObservableCollection<Employee> 
            {
                new Employee{Number=2012,Name="netboy",Sex="boy",BirthYear=1992},
                new Employee{Number=2013,Name="dandan",Sex="girl",BirthYear=2000},
                new Employee{Number=2014,Name="xiaobai",Sex="girl",BirthYear=2012}
            };

            ObservableCollection<Employee> employee2 = new ObservableCollection<Employee> 
            {
                new Employee{Number=2020,Name="kaizi",Sex="girl",BirthYear=2011},
                new Employee{Number=2021,Name="yangzai",Sex="gril",BirthYear=2010}
            };

            this.Add(new Department { DepName = "技术部", Employees = employee1 });
            this.Add(new Department { DepName = "商务部", Employees = employee2 });
            //ObservableCollection<Department> deparment = new ObservableCollection<Department> 
            //{
            //    new Department{DepName="tengfei",Employees=employee1},
            //    new Department{DepName="google",Employees=employee2}
            //};
        }

    }

注意：使用ObservableCollection<T>的时候需要引用命名空间——using System.Collections.ObjectModel;

通过在新建页面的phone:PhoneApplicationPage标记中添加一个命名空间映射。代码如下：

xmlns:local="clr-namespace:数据绑定"//我的项目为“数据绑定”

添加资源字典：

   <phone:PhoneApplicationPage.Resources>
        <local:DepartmentList x:Key="deplist"/>
        <CollectionViewSource x:Key="departmentView"
                              Source="{StaticResource deplist}"/>
        <DataTemplate x:Key="dtEmployees">
            <StackPanel Height="50"
                        HorizontalAlignment="Center"
                        Width="480"
                        VerticalAlignment="Top"
                        Orientation="Horizontal">

                <TextBlock Height="50"
                           HorizontalAlignment="Left"
                           Width="90"
                           Text="{Binding Number}"/>
                <TextBlock Height="50"
                           Width="120"
                           Text="{Binding Name}"/>
                <TextBlock Height="50"
                           Width="120"
                           Text="{Binding BirthYear}"/>
                <TextBlock Height="50"
                           Width="120"
                           Text="{Binding Sex}"/>

            </StackPanel>
        </DataTemplate>
    </phone:PhoneApplicationPage.Resources>

在布局页面中添加如下代码：

            <TextBlock Width="300"
                       Height="50"
                       FontSize="36"
                       Text="请选择部门:"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Margin="10,30,0,0"/>
            <ListBox Name="lb1"
                     Height="100"
                     Width="156"
                     DisplayMemberPath="DepName"
                     ItemsSource="{Binding Source={StaticResource departmentView}}"
                     Margin="40,86,260,0"
                     HorizontalAlignment="Center"
                     VerticalAlignment="Top" FontSize="32" />
            <TextBlock Height="62"
                       Width="111"
                       HorizontalAlignment="Left"
                       VerticalAlignment="Top"
                       Text="{Binding Path=DepName,Source={StaticResource departmentView}}"
                       Foreground="Red" Margin="12,210,0,0" FontSize="32" />

            <TextBlock Height="50"
                       HorizontalAlignment="Right"
                       Text="员工列表"
                       VerticalAlignment="Top" Margin="0,210,169,0" Width="158" FontSize="32" />

            <TextBlock Height="50"
                       HorizontalAlignment="Left"
                       Width="120"
                       Text="性别" Margin="344,278,0,279" FontSize="32" />
            <TextBlock Height="50" Text="出生日期" Margin="204,278,112,279" FontSize="32" />
            <TextBlock Height="50"
                       Width="120"
                       Text="工号" Margin="6,278,330,279" FontSize="32" />
            <TextBlock Height="50"
                       Width="98"
                       Text="名字" Margin="0,278,260,279" HorizontalAlignment="Right" FontSize="32" />

            <ListBox Name="lb2"
                     Height="170"
                     VerticalAlignment="Top"
                     ItemsSource="{Binding Path=Employees,Source={StaticResource departmentView}}"
                     ItemTemplate="{StaticResource dtEmployees}" Margin="12,334,-46,0" FontSize="32" />