WPF 特性------Binding

工业控制中，经常会需要把一个bool  型输入信号的状态显示在面板上，使用wpf 绑定的办法，可简洁实现：

实现步骤：

1，定义类：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;

namespace WpfAppBoolBinding
{
    public class MainViewModel : INotifyPropertyChanged
    {
        private bool _myProperty;

        public bool MyProperty
        {
            get { return _myProperty; }
            set
            {
                if (_myProperty != value)
                {
                    _myProperty = value;
                    OnPropertyChanged();
                }
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = "")
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

    public class TestViewModel
    {
        public MainViewModel MainView { get; set; }
        public int couter { get; set; }
    }
}

2，定义bool  类型转换器：

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;
using System.Windows.Media;

namespace WpfAppBoolBinding
{
    [ValueConversion(typeof(bool), typeof(Brush))]
    public class BooleanToBrushConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
               return (bool)value ? Brushes.Green : Brushes.Red;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

}

3，xml 实现：

<Window x:Class="WpfAppBoolBinding.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:WpfAppBoolBinding" 
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <local:BooleanToBrushConverter x:Key="BooleanToBrushConverter"/>
    </Window.Resources>

    <Grid>
        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">

            <Ellipse Width="50" Height="50" Fill="{Binding MainView.MyProperty, Converter={StaticResource BooleanToBrushConverter}}" Margin="10,30"/>
            
            <Button Content="变换颜色" Width="60" Height="30" Click="Button_Click" Margin="10,30"/>

        </StackPanel>

    </Grid>
</Window>

4，进行Datacontex 绑定：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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.Navigation;
using System.Windows.Shapes;

namespace WpfAppBoolBinding
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        TestViewModel testViewModel = new TestViewModel();

        public MainWindow()
        {
            InitializeComponent();

            testViewModel.MainView = new MainViewModel();

              DataContext = testViewModel;
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            testViewModel.MainView.MyProperty = !testViewModel.MainView.MyProperty;
        }
    }
}