WPF 体验数据邦定

WPF主要做UI，所以数据邦定当然少不了。本节以ListBox为例，介绍数据邦定（和WinForm还是很有区别的哦）。

先建立一个WPFApplication Project. 在Window xaml里添加一个ListBox控件。

<Window x:Class="WpfProject.Test"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Test" Height="300" Width="300" Loaded="Window_Loaded">
    <Grid>
        <ListBox Name="lbxPersons"></ListBox>
    </Grid>
</Window>

引用一个Loaded事件来完成我们的邦定。大家知道，ListBox是一个ItemControl，所以我们通过设置ItemSource来邦定数据。

public partial class Test : Window
    {
        public Test()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            List<Person> persons = new List<Person>{
                new Person{FirstName="jimson",LastName="Ma"},
                new Person{FirstName="Lingxia",LastName="Wang"}
            };

            this.lbxPersons.ItemsSource = persons;
        }
    }

    public class Person{
        public string LastName { set; get; }
        public string FirstName { set; get; }
    }

运行F5，结果：

显然这样是不成的。改进xaml：

<Window x:Class="WpfProject.Test"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Test" Height="300" Width="300" Loaded="Window_Loaded">
    <Grid>
        <ListBox Name="lbxPersons">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding FirstName}" Width="50" />
                        <TextBlock Text="{Binding LastName}" Width="50" />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>

运行F5，结果：

这下正确了。但是有个问题，空值怎么办？看看这个：

<Window x:Class="WpfProject.Test"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Test" Height="300" Width="300" Loaded="Window_Loaded">
    <Grid>
        <ListBox Name="lbxPersons">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding FirstName}" Width="50" />
                        <TextBlock Text="{Binding LastName}" Width="50" />
                        <TextBlock Text="{Binding Age, TargetNullValue='Age Unknown'}"  />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace WpfProject
{
    /// <summary>
    /// Interaction logic for Test.xaml
    /// </summary>
    public partial class Test : Window
    {
        public Test()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            List<Person> persons = new List<Person>{
                new Person{FirstName="jimson",LastName="Ma", Age=23},
                new Person{FirstName="Lingxia",LastName="Wang"}
            };

            this.lbxPersons.ItemsSource = persons;
        }
    }

    public class Person{
        public string LastName { set; get; }
        public string FirstName { set; get; }
        public int? Age { set; get; }
    }

}

运行结果：

应用TargetNullValue，很好的处理了控制信息。

public partial class Test : Window
    {
        public Test()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            List<Person> persons = new List<Person>{
                new Person{FirstName="jimson",LastName="Ma"},
                new Person{FirstName="Lingxia",LastName="Wang"}
            };

            this.lbxPersons.ItemsSource = persons;
        }
    }

    public class Person{
        public string LastName { set; get; }
        public string FirstName { set; get; }
    }