EventArgs クラス
定義
イベント データを格納するクラスの基底クラスを表し、イベント データを含まないイベントに使用する値を提供します。Represents the base class for classes that contain event data, and provides a value to use for events that do not include event data.
public ref class EventArgs
public class EventArgs
[System.Serializable]
public class EventArgs
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class EventArgs
type EventArgs = class
[<System.Serializable>]
type EventArgs = class
[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type EventArgs = class
Public Class EventArgs
- 継承
-
EventArgs
- 派生
- 属性
例
次の例は、クラスから派生するという名前のカスタムイベントデータクラスを示して ThresholdReachedEventArgs
EventArgs います。The following example shows a custom event data class named ThresholdReachedEventArgs
that derives from the EventArgs class. イベントデータクラスのインスタンスは、イベントのイベントハンドラーに渡され ThresholdReached
ます。An instance of the event data class is passed to the event handler for the ThresholdReached
event.
using namespace System;
public ref class ThresholdReachedEventArgs : public EventArgs
{
public:
property int Threshold;
property DateTime TimeReached;
};
public ref class Counter
{
private:
int threshold;
int total;
public:
Counter() {};
Counter(int passedThreshold)
{
threshold = passedThreshold;
}
void Add(int x)
{
total += x;
if (total >= threshold) {
ThresholdReachedEventArgs^ args = gcnew ThresholdReachedEventArgs();
args->Threshold = threshold;
args->TimeReached = DateTime::Now;
OnThresholdReached(args);
}
}
event EventHandler<ThresholdReachedEventArgs^>^ ThresholdReached;
protected:
virtual void OnThresholdReached(ThresholdReachedEventArgs^ e)
{
ThresholdReached(this, e);
}
};
public ref class SampleHandler
{
public:
static void c_ThresholdReached(Object^ sender, ThresholdReachedEventArgs^ e)
{
Console::WriteLine("The threshold of {0} was reached at {1}.",
e->Threshold, e->TimeReached);
Environment::Exit(0);
}
};
void main()
{
Counter^ c = gcnew Counter((gcnew Random())->Next(10));
c->ThresholdReached += gcnew EventHandler<ThresholdReachedEventArgs^>(SampleHandler::c_ThresholdReached);
Console::WriteLine("press 'a' key to increase total");
while (Console::ReadKey(true).KeyChar == 'a') {
Console::WriteLine("adding one");
c->Add(1);
}
}
using System;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
Counter c = new Counter(new Random().Next(10));
c.ThresholdReached += c_ThresholdReached;
Console.WriteLine("press 'a' key to increase total");
while (Console.ReadKey(true).KeyChar == 'a')
{
Console.WriteLine("adding one");
c.Add(1);
}
}
static void c_ThresholdReached(object sender, ThresholdReachedEventArgs e)
{
Console.WriteLine("The threshold of {0} was reached at {1}.", e.Threshold, e.TimeReached);
Environment.Exit(0);
}
}
class Counter
{
private int threshold;
private int total;
public Counter(int passedThreshold)
{
threshold = passedThreshold;
}
public void Add(int x)
{
total += x;
if (total >= threshold)
{
ThresholdReachedEventArgs args = new ThresholdReachedEventArgs();
args.Threshold = threshold;
args.TimeReached = DateTime.Now;
OnThresholdReached(args);
}
}
protected virtual void OnThresholdReached(ThresholdReachedEventArgs e)
{
EventHandler<ThresholdReachedEventArgs> handler = ThresholdReached;
if (handler != null)
{
handler(this, e);
}
}
public event EventHandler<ThresholdReachedEventArgs> ThresholdReached;
}
public class ThresholdReachedEventArgs : EventArgs
{
public int Threshold { get; set; }
public DateTime TimeReached { get; set; }
}
}
Module Module1
Sub Main()
Dim c As Counter = New Counter(New Random().Next(10))
AddHandler c.ThresholdReached, AddressOf c_ThresholdReached
Console.WriteLine("press 'a' key to increase total")
While Console.ReadKey(True).KeyChar = "a"
Console.WriteLine("adding one")
c.Add(1)
End While
End Sub
Sub c_ThresholdReached(sender As Object, e As ThresholdReachedEventArgs)
Console.WriteLine("The threshold of {0} was reached at {1}.", e.Threshold, e.TimeReached)
Environment.Exit(0)
End Sub
End Module
Class Counter
Private threshold As Integer
Private total As Integer
Public Sub New(passedThreshold As Integer)
threshold = passedThreshold
End Sub
Public Sub Add(x As Integer)
total = total + x
If (total >= threshold) Then
Dim args As ThresholdReachedEventArgs = New ThresholdReachedEventArgs()
args.Threshold = threshold
args.TimeReached = DateTime.Now
OnThresholdReached(args)
End If
End Sub
Protected Overridable Sub OnThresholdReached(e As ThresholdReachedEventArgs)
RaiseEvent ThresholdReached(Me, e)
End Sub
Public Event ThresholdReached As EventHandler(Of ThresholdReachedEventArgs)
End Class
Class ThresholdReachedEventArgs
Inherits EventArgs
Public Property Threshold As Integer
Public Property TimeReached As DateTime
End Class
注釈
このクラスは、イベントデータを表すすべてのクラスの基本クラスとして機能します。This class serves as the base class for all classes that represent event data. たとえば、クラスは System.AssemblyLoadEventArgs から派生 EventArgs し、アセンブリ読み込みイベントのデータを保持するために使用されます。For example, the System.AssemblyLoadEventArgs class derives from EventArgs and is used to hold the data for assembly load events. カスタムイベントデータクラスを作成するには、クラスから派生したクラスを作成 EventArgs し、必要なデータを格納するためのプロパティを指定します。To create a custom event data class, create a class that derives from the EventArgs class and provide the properties to store the necessary data. カスタムイベントデータクラスの名前は、で終わる必要があり EventArgs
ます。The name of your custom event data class should end with EventArgs
.
データが含まれていないオブジェクトを渡すには、フィールドを使用し Empty ます。To pass an object that does not contain any data, use the Empty field.
イベントの詳細については、 イベントの処理と発生 に関する記事を参照してください。For more information about events, see the Handling and Raising Events article.
コンストラクター
EventArgs() |
EventArgs クラスの新しいインスタンスを初期化します。Initializes a new instance of the EventArgs class. |
フィールド
Empty |
イベント データのないイベントに使用する値を提供します。Provides a value to use with events that do not have event data. |
メソッド
Equals(Object) |
指定されたオブジェクトが現在のオブジェクトと等しいかどうかを判断します。Determines whether the specified object is equal to the current object. (継承元 Object) |
GetHashCode() |
既定のハッシュ関数として機能します。Serves as the default hash function. (継承元 Object) |
GetType() |
現在のインスタンスの Type を取得します。Gets the Type of the current instance. (継承元 Object) |
MemberwiseClone() |
現在の Object の簡易コピーを作成します。Creates a shallow copy of the current Object. (継承元 Object) |
ToString() |
現在のオブジェクトを表す文字列を返します。Returns a string that represents the current object. (継承元 Object) |