protected void SetProperty<T>(ref T field,T value, [CallerMemberName] string propName=null) { if(!EqualityComparer<T>.Default.Equals (field, value)) { field= value; var handler = PropertyChanged; if(handler!=null) { handler?.Invoke (this, new PropertyChangedEventArgs(propName)); } } }
Whole code
//xaml <Window x:Class="WpfApp73.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:WpfApp73" Title="MainWindow" Height="850" Width="800"> <StackPanel Margin="100" TextBlock.FontSize="20"> <TextBlock Text="{Binding Name}"/> <TextBlock Text="{Binding Age}"/> <Button Content="Increment Age" Click="IncrementAgeClick"/> </StackPanel> </Window> using System; using System.Collections.Generic; using System.ComponentModel; using System.Linq; using System.Linq.Expressions; using System.Runtime.CompilerServices; 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 WpfApp73 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { private Person _person; public MainWindow() { InitializeComponent(); _person = new Person() { Age = 17, Name = "Fred" }; this.DataContext= _person; } private void IncrementAgeClick(object sender, RoutedEventArgs e) { _person.Age++; } } class Person:INotifyPropertyChanged { public string Name { get; set; } private int age; public int Age { get { return age; } set { SetProperty(ref age, value); } } public event PropertyChangedEventHandler PropertyChanged; public void OnPropertyChanged(string propertyName) { var handler=PropertyChanged; if (handler != null) { handler?.Invoke(this, new PropertyChangedEventArgs(propertyName)); } } protected void SetProperty<T>(ref T field,T value, [CallerMemberName] string propName=null) { if(!EqualityComparer<T>.Default.Equals (field, value)) { field= value; var handler = PropertyChanged; if(handler!=null) { handler?.Invoke (this, new PropertyChangedEventArgs(propName)); } } } } }
标签:compare,Windows,System,value,field,handler,notify,using,assign From: https://www.cnblogs.com/Fred1987/p/18168017