FirstChanceExceptionEventArgs 類別

  • 參考

定義

命名空間:
System.Runtime.ExceptionServices
組件:
System.Runtime.dll
組件:
mscorlib.dll
組件:
netstandard.dll
來源:
FirstChanceExceptionEventArgs.cs
來源:
FirstChanceExceptionEventArgs.cs
來源:
FirstChanceExceptionEventArgs.cs

在 Common Language Runtime 開始搜尋事件處理常式之前，為第一次發生 Managed 例外狀況時所引發的通知事件提供相關資料。

public ref class FirstChanceExceptionEventArgs : EventArgs
public class FirstChanceExceptionEventArgs : EventArgs
type FirstChanceExceptionEventArgs = class
    inherit EventArgs
Public Class FirstChanceExceptionEventArgs
Inherits EventArgs
繼承
Object
EventArgs
FirstChanceExceptionEventArgs

範例

下列範例會使用每個應用程式域中的物件，建立一系列名為 Child_0Child_3Worker 的應用程式域。 每個 Worker 物件都有下一個應用程式域中物件的參考 Worker ，但最後一個應用程式域中的 除外 Worker 。 除了 之外 Child_1 ，事件 FirstChanceException 會處理于所有應用程式域中。

建立應用程式域之後，預設應用程式域會呼叫 TestException 第一個子應用程式域的方法。 每個 Worker 物件 TestException 都會呼叫下一個 方法，直到最後 Worker 一個擲回已處理或未處理的例外狀況為止。 因此，目前的執行緒會通過所有應用程式域，並 TestException 新增至每個應用程式域中的堆疊。

當最後一個 Worker 物件處理例外狀況時，事件 FirstChanceException 只會在最後一個應用程式域中引發。 其他應用程式域永遠不會有機會處理例外狀況，因此不會引發事件。

當最後一個 Worker 物件未處理例外狀況時，事件 FirstChanceException 會在具有事件處理常式的每個應用程式域中引發。 在每個事件處理常式完成之後，堆疊會繼續回溯，直到預設應用程式域攔截到例外狀況為止。

注意

若要查看堆疊顯示隨著事件更接近預設應用程式域而增加的方式，請在事件處理常式中 FirstChanceHandler 變更 e.Exception.Message 為 e.Exception 。 請注意，在跨應用程式域界限呼叫 時 TestException ，它會出現兩次：一次用於 Proxy，一次用於存根。

using System;
using System.Reflection;
using System.Runtime.ExceptionServices;

class FirstChanceExceptionSnippet
{
    static void Main()
    {
        AppDomain.CurrentDomain.FirstChanceException += FirstChanceHandler;

        // Create a set of application domains, with a Worker object in each one.
        // Each Worker object creates the next application domain.
        AppDomain ad = AppDomain.CreateDomain("AD0");
        Worker w = (Worker) ad.CreateInstanceAndUnwrap(
                                typeof(Worker).Assembly.FullName, "Worker");
        w.Initialize(0, 3);

        Console.WriteLine("\r\nThe last application domain throws an exception and catches it:");
        Console.WriteLine();
        w.TestException(true);

        try
        {
            Console.WriteLine(
                "\r\nThe last application domain throws an exception and does not catch it:");
            Console.WriteLine();
            w.TestException(false);
        }
        catch (ArgumentException ex)
        {
            Console.WriteLine("ArgumentException caught in {0}: {1}",
                AppDomain.CurrentDomain.FriendlyName, ex.Message);
        }
    }

    static void FirstChanceHandler(object source, FirstChanceExceptionEventArgs e)
    {
        Console.WriteLine("FirstChanceException event raised in {0}: {1}",
            AppDomain.CurrentDomain.FriendlyName, e.Exception.Message);
    }
}

public class Worker : MarshalByRefObject
{
    private AppDomain ad = null;
    private Worker w = null;

    public void Initialize(int count, int max)
    {
        // Handle the FirstChanceException event in all application domains except
        // AD1.
        if (count != 1)
        {
            AppDomain.CurrentDomain.FirstChanceException += FirstChanceHandler;
        }

        // Create another application domain, until the maximum is reached.
        // Field w remains null in the last application domain, as a signal
        // to TestException().
        if (count < max)
        {
            int next = count + 1;
            ad = AppDomain.CreateDomain("AD" + next);
            w = (Worker) ad.CreateInstanceAndUnwrap(
                             typeof(Worker).Assembly.FullName, "Worker");
            w.Initialize(next, max);
        }
    }

    public void TestException(bool handled)
    {
        // As long as there is another application domain, call TestException() on
        // its Worker object. When the last application domain is reached, throw a
        // handled or unhandled exception.
        if (w != null)
        {
            w.TestException(handled);
        }
        else if (handled)
        {
            try
            {
                throw new ArgumentException("Thrown in " + AppDomain.CurrentDomain.FriendlyName);
            }
            catch (ArgumentException ex)
            {
                Console.WriteLine("ArgumentException caught in {0}: {1}",
                    AppDomain.CurrentDomain.FriendlyName, ex.Message);
            }
        }
        else
        {
            throw new ArgumentException("Thrown in " + AppDomain.CurrentDomain.FriendlyName);
        }
    }

    static void FirstChanceHandler(object source, FirstChanceExceptionEventArgs e)
    {
        Console.WriteLine("FirstChanceException event raised in {0}: {1}",
            AppDomain.CurrentDomain.FriendlyName, e.Exception.Message);
    }
}

/* This example produces output similar to the following:

The last application domain throws an exception and catches it:

FirstChanceException event raised in AD3: Thrown in AD3
ArgumentException caught in AD3: Thrown in AD3

The last application domain throws an exception and does not catch it:

FirstChanceException event raised in AD3: Thrown in AD3
FirstChanceException event raised in AD2: Thrown in AD3
FirstChanceException event raised in AD0: Thrown in AD3
FirstChanceException event raised in Example.exe: Thrown in AD3
ArgumentException caught in Example.exe: Thrown in AD3
 */

Imports System.Reflection
Imports System.Runtime.ExceptionServices

Class Example

    Shared Sub Main()
    
        AddHandler AppDomain.CurrentDomain.FirstChanceException, AddressOf FirstChanceHandler

        ' Create a set of application domains, with a Worker object in each one.
        ' Each Worker object creates the next application domain.
        Dim ad As AppDomain = AppDomain.CreateDomain("AD0")
        Dim w As Worker = CType(ad.CreateInstanceAndUnwrap(
                                GetType(Worker).Assembly.FullName, "Worker"),
                                Worker)
        w.Initialize(0, 3)

        Console.WriteLine(vbCrLf & "The last application domain throws an exception and catches it:")
        Console.WriteLine()
        w.TestException(true)

        Try
            Console.WriteLine(vbCrLf & 
                "The last application domain throws an exception and does not catch it:")
            Console.WriteLine()
            w.TestException(false) 

        Catch ex As ArgumentException
        
            Console.WriteLine("ArgumentException caught in {0}: {1}", 
                AppDomain.CurrentDomain.FriendlyName, ex.Message)
        End Try
    End Sub

    Shared Sub FirstChanceHandler(ByVal source As Object, 
                                  ByVal e As FirstChanceExceptionEventArgs)
    
        Console.WriteLine("FirstChanceException event raised in {0}: {1}",
            AppDomain.CurrentDomain.FriendlyName, e.Exception.Message)
    End Sub
End Class

Public Class Worker
    Inherits MarshalByRefObject

    Private ad As AppDomain = Nothing
    Private w As Worker = Nothing

    Public Sub Initialize(ByVal count As Integer, ByVal max As Integer)
    
        ' Handle the FirstChanceException event in all application domains except
        ' AD1.
        If count <> 1
        
            AddHandler AppDomain.CurrentDomain.FirstChanceException, AddressOf FirstChanceHandler

        End If

        ' Create another application domain, until the maximum is reached.
        ' Field w remains Nothing in the last application domain, as a signal 
        ' to TestException(). 
        If count < max
            Dim nextAD As Integer = count + 1
            ad = AppDomain.CreateDomain("AD" & nextAD)
            w = CType(ad.CreateInstanceAndUnwrap(
                      GetType(Worker).Assembly.FullName, "Worker"),
                      Worker)
            w.Initialize(nextAD, max)
        End If
    End Sub

    Public Sub TestException(ByVal handled As Boolean)
    
        ' As long as there is another application domain, call TestException() on
        ' its Worker object. When the last application domain is reached, throw a
        ' handled or unhandled exception.
        If w IsNot Nothing
        
            w.TestException(handled)

        Else If handled
        
            Try
                Throw New ArgumentException("Thrown in " & AppDomain.CurrentDomain.FriendlyName)

            Catch ex As ArgumentException
            
                Console.WriteLine("ArgumentException caught in {0}: {1}", 
                    AppDomain.CurrentDomain.FriendlyName, ex.Message)
            End Try
        Else
        
            Throw New ArgumentException("Thrown in " & AppDomain.CurrentDomain.FriendlyName)
        End If
    End Sub

    Shared Sub FirstChanceHandler(ByVal source As Object, 
                                  ByVal e As FirstChanceExceptionEventArgs)
    
        Console.WriteLine("FirstChanceException event raised in {0}: {1}",
            AppDomain.CurrentDomain.FriendlyName, e.Exception.Message)
    End Sub
End Class

' This example produces output similar to the following:
'
'The last application domain throws an exception and catches it:
'
'FirstChanceException event raised in AD3: Thrown in AD3
'ArgumentException caught in AD3: Thrown in AD3
'
'The last application domain throws an exception and does not catch it:
'
'FirstChanceException event raised in AD3: Thrown in AD3
'FirstChanceException event raised in AD2: Thrown in AD3
'FirstChanceException event raised in AD0: Thrown in AD3
'FirstChanceException event raised in Example.exe: Thrown in AD3
'ArgumentException caught in Example.exe: Thrown in AD3

備註

這個類別會為具有例外狀況存取權的事件 AppDomain.FirstChanceException 提供例外狀況處理常式。

建構函式

FirstChanceExceptionEventArgs(Exception)

使用指定的例外狀況，初始化 FirstChanceExceptionEventArgs 類別的新執行個體。

屬性

Exception

與 Managed 程式碼所擲回的例外狀況對應的 Managed 例外狀況物件。

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

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