编辑“︁C Sharp 事件基础”︁（章节）

== .NET内置事件模式 ==
.NET框架提供了标准的事件模式：
* 使用`EventHandler`或`EventHandler<TEventArgs>`委托
* 事件参数应继承自`EventArgs`

=== 标准示例 ===
<syntaxhighlight lang="csharp">
public class TemperatureMonitor
{
    // 使用标准EventHandler<T>委托
    public event EventHandler<TemperatureChangedEventArgs> TemperatureChanged;
    
    private double currentTemp;
    
    public double CurrentTemperature
    {
        get => currentTemp;
        set
        {
            if (currentTemp != value)
            {
                currentTemp = value;
                OnTemperatureChanged(new TemperatureChangedEventArgs(value));
            }
        }
    }
    
    protected virtual void OnTemperatureChanged(TemperatureChangedEventArgs e)
    {
        TemperatureChanged?.Invoke(this, e);
    }
}

// 自定义事件参数
public class TemperatureChangedEventArgs : EventArgs
{
    public double NewTemperature { get; }
    
    public TemperatureChangedEventArgs(double newTemp)
    {
        NewTemperature = newTemp;
    }
}

// 使用示例
public class Program
{
    public static void Main()
    {
        var monitor = new TemperatureMonitor();
        monitor.TemperatureChanged += Monitor_TemperatureChanged;
        
        monitor.CurrentTemperature = 25.5;  // 会触发事件
        monitor.CurrentTemperature = 30.0;  // 会触发事件
    }
    
    private static void Monitor_TemperatureChanged(object sender, TemperatureChangedEventArgs e)
    {
        Console.WriteLine($"温度变更为: {e.NewTemperature}°C");
    }
}
</syntaxhighlight>

'''输出结果:'''
<pre>
温度变更为: 25.5°C
温度变更为: 30°C
</pre>