Winphone开发之数据绑定(3)

这篇文章主要介绍怎么自定义Binding的源，通过CS代码指定Binding的源来初步构造整个数据绑定的流程。

下面是要绑定的类：

using System;using System.Collections.Generic;using System.ComponentModel;using System.Linq;using System.Text;using System.Threading.Tasks;namespace BindingLearning{    public class Person : INotifyPropertyChanged      {        private String name;        public event PropertyChangedEventHandler PropertyChanged;          public String Name        {            get            {                return name;            }            set            {                name = value;                this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs("Name"));            }        }    }}

可以看到该类继承了INotifyPropertyChanged接口，然后声明了事件PropertyChanged，其中PropertyChangedEventHandler会当属性改变的时候抛出事件来通知UI，其中指明了属性名称为Name。

综上，该类会在Name属性被设置的时候发送数据更改的消息。

下面是XAML：

<phone:PhoneApplicationPage    x:Class="BindingLearning.MainPage"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    mc:Ignorable="d"    FontFamily="{StaticResource PhoneFontFamilyNormal}"    FontSize="{StaticResource PhoneFontSizeNormal}"    Foreground="{StaticResource PhoneForegroundBrush}"    SupportedOrientations="Portrait" Orientation="Portrait"    shell:SystemTray.IsVisible="True">    <Grid HorizontalAlignment="Left" Height="768" VerticalAlignment="Top" Width="480">        <Button Name="bt" Content="Button" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="178,470,0,0" Click="bt_Click"/>        <TextBox Name="tb" HorizontalAlignment="Left" Height="72" Margin="14,222,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="456"/>    </Grid></phone:PhoneApplicationPage>

只是简单声明了一个Button和一个TextBox

重要的是隐藏的CS文件：

using System;using System.Collections.Generic;using System.Linq;using System.Net;using System.Windows;using System.Windows.Controls;using System.Windows.Navigation;using Microsoft.Phone.Controls;using Microsoft.Phone.Shell;using BindingLearning.Resources;using System.Windows.Data;namespace BindingLearning{    public partial class MainPage : PhoneApplicationPage    {        private Person p;        // 构造函数        public MainPage()        {            InitializeComponent();            p = new Person();            Binding binding = new Binding();            binding.Source = p;            binding.Path = new PropertyPath("Name");            this.tb.SetBinding(TextBox.TextProperty, binding);        }        private void bt_Click(object sender, RoutedEventArgs e)        {            p.Name += "hello";        }            }}

构造了Person的实例p作为数据的源，然后制定里面的Name参数作为Path（Person里面有Name属性，并且我们刚刚也为它设置了监听），最后用SetBinding使得TextBox的TextProperty依赖属性和刚刚构造好的binding关联起来，最后的效果是，当p的Name属性被设置的时候，TextBox的Text依赖属性也会跟随改变。

然后我们监听了Button的点击事件，每点击一次就改变一下p的Name属性。

所以上面代码总体效果：

每当我点击一次Button，TextBox就会在原来的基础上不断地append字符串hello。

实例二：

和上面的实例差不多，但是用了DataContext，没有了Path

<phone:PhoneApplicationPage    x:Class="PhoneApp6.MainPage"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    mc:Ignorable="d"    FontFamily="{StaticResource PhoneFontFamilyNormal}"    FontSize="{StaticResource PhoneFontSizeNormal}"    Foreground="{StaticResource PhoneForegroundBrush}"    SupportedOrientations="Portrait" Orientation="Portrait"    shell:SystemTray.IsVisible="True">    <!--LayoutRoot 是包含所有页面内容的根网格-->    <Grid x:Name="LayoutRoot" Background="Transparent">        <Grid.RowDefinitions>            <RowDefinition Height="Auto"/>            <RowDefinition Height="*"/>        </Grid.RowDefinitions>        <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28"/>        <!--ContentPanel - 在此处放置其他内容-->        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">            <TextBox Name="Tb" Text="{Binding Name}" HorizontalAlignment="Left" Height="72" Margin="0,241,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="456"/>        </Grid>        <Button Content="Button" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="170,422,0,0" Grid.Row="1" Click="Button_Click"/>            </Grid></phone:PhoneApplicationPage>

using System;using System.Collections.Generic;using System.Linq;using System.Net;using System.Windows;using System.Windows.Controls;using System.Windows.Navigation;using Microsoft.Phone.Controls;using Microsoft.Phone.Shell;using PhoneApp6.Resources;namespace PhoneApp6{    public partial class MainPage : PhoneApplicationPage    {        private Person p;        // 构造函数        public MainPage()        {            InitializeComponent();        }        protected override void OnNavigatedTo(NavigationEventArgs e)        {            base.OnNavigatedTo(e);            p = new Person() { Name = "Sirius" };            Tb.DataContext = p;        }        private void Button_Click(object sender, RoutedEventArgs e)        {            p.Name = DateTime.Now.Millisecond.ToString();        }            }}

using System;using System.Collections.Generic;using System.ComponentModel;using System.Linq;using System.Text;using System.Threading.Tasks;namespace PhoneApp6{    public class Person : INotifyPropertyChanged    {        private String _name;        public String Name        {            get            {                return _name;            }            set            {                _name = value;                if (PropertyChanged != null)                {                    PropertyChanged(this, new PropertyChangedEventArgs("Name"));                }            }        }        public event PropertyChangedEventHandler PropertyChanged;    }}