事件2 (标准 EventHandler)

namespace System

{

// Summary:

// Represents the method that will handle an event.

//

// Parameters:

// sender:

// The source of the event.

//

// e:

// An System.EventArgs that contains the event data.

//

// Type parameters:

// TEventArgs:

// The type of the event data generated by the event.

[Serializable]

public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e); //注意这个是模板

}

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namespace System

{

// Summary:

// System.EventArgs is the base class for classes containing event data.

[Serializable]

[ComVisible(true)]

public class EventArgs

{

// Summary:

// Represents an event with no event data.

public static readonly EventArgs Empty;

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// Summary:

// Initializes a new instance of the System.EventArgs class.

public EventArgs();

}

}

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/////////////////////////////////////////////////////////////////

public class IncrementerEventArgs : EventArgs // Custom class derived from EventArgs

{

public int IterationCount { get; set; } // Stores an integer

}

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class Incrementer

{

public event EventHandler<IncrementerEventArgs> CountedADozen;

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public void DoCount()

{

IncrementerEventArgs args = new IncrementerEventArgs();

for ( int i=1; i < 100; i++ )

if ( i % 12 == 0 && CountedADozen != null )

{

args.IterationCount = i;

CountedADozen( this, args );

}

}

}

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class Dozens

{

public int DozensCount { get; private set; }

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public Dozens( Incrementer incrementer )

{

DozensCount = 0;

incrementer.CountedADozen += IncrementDozensCount;

}

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void IncrementDozensCount( object source, IncrementerEventArgs e )

{

Console.WriteLine( "Incremented at iteration: {0} in {1}",

e.IterationCount, source.ToString() );

DozensCount++;

}

}

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class Program

{

static void Main()

{

Incrementer incrementer = new Incrementer();

Dozens dozensCounter = new Dozens( incrementer );

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incrementer.DoCount();

Console.WriteLine( "Number of dozens = {0}",

dozensCounter.DozensCount );

}

}