WPF例6-布尔数据转换为显示红绿方格

一、如果需要转换数据格式，则需要新建一个数据转换类并且实现IValueConverter接口，这里新建了一个BoolToBrushConverter类，如果数据为true，则返回绿色画刷，数据为false，返回红色画刷，然后在矩形的Fill属性中绑定数据，同时设定Converter属性为我们的BoolToBrushConverter类。

MainWindow.xaml.cs文件代码

using System;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Windows;
using System.Windows.Data;
using System.Windows.Media;

namespace WpfApp3
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public Students students { get; set; }
        public MainWindow()
        {
            InitializeComponent();
            DataContext = this; //设置窗口数据上下文为当前对象，ListBox控件会自动查找到students属性
            students = new Students();
            //添加几条数据
            students.Add(new Student { IsGood = false, Name = "Tom" });
            students.Add(new Student { IsGood = false, Name = "Peter" });
            students.Add(new Student { IsGood = true, Name = "Hank" });
            students.Add(new Student { IsGood = false, Name = "Nancy" });
            students.Add(new Student { IsGood = true, Name = "Tom" });

        }
    }
    public class Student
    {
        public string Name { get; set; }
        public bool IsGood { get; set; }
    }
    public class Students : ObservableCollection<Student> { }
    //数据转换类
    public class BoolToBrushConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return (bool)value ? Brushes.Green : Brushes.Red;//转换器主要逻辑
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();//自动生成，本例中无需用到
        }
    }
}

MainWindow.xaml文件代码

<Window x:Class="WpfApp3.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp3"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <ResourceDictionary>
            <local:BoolToBrushConverter x:Key="BoolToBrushConverter"/>
        </ResourceDictionary>
    </Window.Resources>
    <Grid>
        <ListBox ItemsSource="{Binding students}" HorizontalAlignment="Left" Height="271" Margin="158,83,0,0" VerticalAlignment="Top" Width="207">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <StackPanel Orientation="Horizontal">
                            <Label Content="{Binding Name}" Width="100"/>
                            <Rectangle Width="10" Height="10" Margin="5" Fill="{Binding IsGood, Converter={StaticResource BoolToBrushConverter}}"/>
                        </StackPanel>
                    </Grid>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>

代码效果如下：