EventArgs 類別

參考

定義

命名空間:: System

組件:: System.Runtime.dll

組件:: mscorlib.dll

組件:: netstandard.dll

來源:: EventArgs.cs

來源:: EventArgs.cs

來源:: EventArgs.cs

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

代表包含事件資料之類別的基底類別，並提供要用於不包含事件資料之事件的值。

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

繼承: Object
EventArgs

衍生: Microsoft.VisualBasic.ApplicationServices.ApplyApplicationDefaultsEventArgs

Microsoft.VisualBasic.ApplicationServices.StartupNextInstanceEventArgs

Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs

Microsoft.Win32.PowerModeChangedEventArgs

Microsoft.Win32.SessionEndedEventArgs

更多…

屬性: SerializableAttribute ComVisibleAttribute

範例

下列範例顯示衍生自 EventArgs 類別的ThresholdReachedEventArgs自定義事件數據類別。事件數據類別的實例會傳遞至事件的事件處理程式 ThresholdReached 。

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; }
    }
}

open System

type ThresholdReachedEventArgs(threshold, timeReached) =
    inherit EventArgs()
    member _.Threshold = threshold
    member _.TimeReached = timeReached

type Counter(threshold) =
    let mutable total = 0

    let thresholdReached = Event<_>()

    member this.Add(x) =
        total <- total + x
        if total >= threshold then
            let args = ThresholdReachedEventArgs(threshold, DateTime.Now)
            thresholdReached.Trigger(this, args)

    [<CLIEvent>]
    member _.ThresholdReached = thresholdReached.Publish

let c_ThresholdReached(sender, e: ThresholdReachedEventArgs) =
    printfn $"The threshold of {e.Threshold} was reached at {e.TimeReached}."
    exit 0

let c = Counter(Random().Next 10)
c.ThresholdReached.Add c_ThresholdReached

printfn "press 'a' key to increase total"
while Console.ReadKey(true).KeyChar = 'a' do
    printfn "adding one"
    c.Add 1

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

備註

這個類別可作為代表事件數據之所有類別的基類。例如，類別 System.AssemblyLoadEventArgs 衍生自 EventArgs ，並用來保存元件載入事件的數據。若要建立自定義事件數據類別，請建立衍生自類別的 EventArgs 類別，並提供屬性來儲存必要的數據。自訂事件數據類別的名稱應該以 EventArgs結尾。

若要傳遞不包含任何資料的物件，請使用 Empty 欄位。

如需事件的詳細資訊，請參閱處理和引發事件一文。

建構函式

EventArgs()

初始化 EventArgs 類別的新執行個體。

欄位

Empty

提供值以搭配沒有事件資料的事件使用。

方法

Equals(Object)	判斷指定的物件是否等於目前的物件。 (繼承來源 Object)
GetHashCode()	做為預設雜湊函式。 (繼承來源 Object)
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)

適用於

共用方式為

EventArgs 類別

定義

範例

備註

建構函式

欄位

方法

適用於

另請參閱

其他資源