C# standard event pattern « event « Language Basics

Event parameter should subclass System.EventArgs to create its own event data.


public class ValueChangedEventArgs : System.EventArgs
{
    public readonly string str;

    public ValueChangedEventArgs(string str)
    {
        this.str = str;
    }
}

 
public delegate void EventHandler<TEventArgs>(object source, TEventArgs e) where TEventArgs : EventArgs;

 
using System;

public class ValueChangedEventArgs : System.EventArgs
{
    public readonly string str;

    public ValueChangedEventArgs(string str)
    {
        this.str = str;
    }
}

class Printer
{
    public event EventHandler<ValueChangedEventArgs> ValuesChanged;
    private string stringValue;

    protected virtual void OnPriceChanged(ValueChangedEventArgs e)
    {
        if (ValuesChanged != null)
            ValuesChanged(this, e);
    }


    public string StringValue
    {
        get
        {
            return stringValue;
        }
        set
        {
            OnPriceChanged(new ValueChangedEventArgs(value));
            stringValue = value;
        }
    }
}
class Test
{
    static void stock_PriceChanged(object sender, ValueChangedEventArgs e)
    {
        Console.WriteLine("event!");
    }

    static void Main()
    {

        Printer p = new Printer();

        p.StringValue = "java2s.com";

    }
}