AggregateException.Flatten Método
Definición
Importante
Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.
Aplana una instancia AggregateException en una única instancia nueva.
public:
AggregateException ^ Flatten();public AggregateException Flatten ();member this.Flatten : unit -> AggregateExceptionPublic Function Flatten () As AggregateExceptionDevoluciones
Nueva instancia AggregateException aplanada.
Ejemplos
En el ejemplo siguiente, las instancias anidadas de AggregateException se reducen y se controlan en un solo bucle.
using System;
using System.Threading.Tasks;
public class Example
{
public static void Main()
{
var task1 = Task.Factory.StartNew(() => {
var child1 = Task.Factory.StartNew(() => {
var child2 = Task.Factory.StartNew(() => {
// This exception is nested inside three AggregateExceptions.
throw new CustomException("Attached child2 faulted.");
}, TaskCreationOptions.AttachedToParent);
// This exception is nested inside two AggregateExceptions.
throw new CustomException("Attached child1 faulted.");
}, TaskCreationOptions.AttachedToParent);
});
try {
task1.Wait();
}
catch (AggregateException ae) {
foreach (var e in ae.Flatten().InnerExceptions) {
if (e is CustomException) {
Console.WriteLine(e.Message);
}
else {
throw;
}
}
}
}
}
public class CustomException : Exception
{
public CustomException(String message) : base(message)
{}
}
// The example displays the following output:
// Attached child1 faulted.
// Attached child2 faulted.
open System
open System.Threading.Tasks
type CustomException(message) =
inherit Exception(message)
let task1 =
Task.Factory.StartNew (fun () ->
let child1 =
Task.Factory.StartNew(
(fun () ->
let child2 =
Task.Factory.StartNew(
(fun () -> raise (CustomException "Attached child2 faulted,")),
TaskCreationOptions.AttachedToParent
)
raise (CustomException "Attached child1 faulted.")),
TaskCreationOptions.AttachedToParent
)
()
)
try
task1.Wait()
with
| :? AggregateException as ae ->
for e in ae.Flatten().InnerExceptions do
if e :? CustomException then
printfn "%s" e.Message
else
reraise()
// The example displays the following output:
// Attached child1 faulted.
// Attached child2 faulted.
Imports System.Threading.Tasks
Module Example
Public Sub Main()
Dim task1 = Task.Factory.StartNew(Sub()
Dim child1 = Task.Factory.StartNew(Sub()
Dim child2 = Task.Factory.StartNew(Sub()
Throw New CustomException("Attached child2 faulted.")
End Sub,
TaskCreationOptions.AttachedToParent)
Throw New CustomException("Attached child1 faulted.")
End Sub,
TaskCreationOptions.AttachedToParent)
End Sub)
Try
task1.Wait()
Catch ae As AggregateException
For Each ex In ae.Flatten().InnerExceptions
If TypeOf ex Is CustomException Then
Console.WriteLine(ex.Message)
Else
Throw
End If
Next
End Try
End Sub
End Module
Class CustomException : Inherits Exception
Public Sub New(s As String)
MyBase.New(s)
End Sub
End Class
' The example displays the following output:
' Attached child1 faulted.
' Attached child2 faulted.
También puede utilizar el método AggregateException.Flatten para volver a generar las excepciones internas de varias instancias de AggregateException iniciadas por varias tareas en una sola instancia de AggregateException, como se muestra en el ejemplo siguiente.
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
public class Example2
{
public static void Main()
{
try {
ExecuteTasks();
}
catch (AggregateException ae) {
foreach (var e in ae.InnerExceptions) {
Console.WriteLine("{0}:\n {1}", e.GetType().Name, e.Message);
}
}
}
static void ExecuteTasks()
{
// Assume this is a user-entered String.
String path = @"C:\";
List<Task> tasks = new List<Task>();
tasks.Add(Task.Run(() => {
// This should throw an UnauthorizedAccessException.
return Directory.GetFiles(path, "*.txt",
SearchOption.AllDirectories);
}));
tasks.Add(Task.Run(() => {
if (path == @"C:\")
throw new ArgumentException("The system root is not a valid path.");
return new String[] { ".txt", ".dll", ".exe", ".bin", ".dat" };
}));
tasks.Add(Task.Run(() => {
throw new NotImplementedException("This operation has not been implemented.");
}));
try {
Task.WaitAll(tasks.ToArray());
}
catch (AggregateException ae) {
throw ae.Flatten();
}
}
}
// The example displays the following output:
// UnauthorizedAccessException:
// Access to the path 'C:\Documents and Settings' is denied.
// ArgumentException:
// The system root is not a valid path.
// NotImplementedException:
// This operation has not been implemented.
open System
open System.IO
open System.Threading.Tasks
let executeTasks () =
// Assume this is a user-entered String.
let path = @"C:\"
let tasks =
[| Task.Run (fun () ->
// This should throw an UnauthorizedAccessException.
Directory.GetFiles(path, "*.txt", SearchOption.AllDirectories))
:> Task
Task.Run (fun () ->
if path = @"C:\" then
raise (ArgumentException "The system root is not a valid path.")
[| ".txt"; ".dll"; ".exe"; ".bin"; ".dat" |])
:> Task
Task.Run(fun () -> raise (NotImplementedException "This operation has not been implemented")) |]
try
Task.WaitAll(tasks)
with
| :? AggregateException as ae -> raise (ae.Flatten())
try
executeTasks ()
with
| :? AggregateException as ae ->
for e in ae.InnerExceptions do
printfn $"{e.GetType().Name}:\n {e.Message}"
// The example displays the following output:
// UnauthorizedAccessException:
// Access to the path 'C:\Documents and Settings' is denied.
// ArgumentException:
// The system root is not a valid path.
// NotImplementedException:
// This operation has not been implemented.
Imports System.Collections.Generic
Imports System.IO
Imports System.Threading.Tasks
Module Example
Public Sub Main()
Try
ExecuteTasks()
Catch ae As AggregateException
For Each e In ae.InnerExceptions
Console.WriteLine("{0}:{2} {1}", e.GetType().Name, e.Message,
vbCrLf)
Next
End Try
End Sub
Sub ExecuteTasks()
' Assume this is a user-entered String.
Dim path = "C:\"
Dim tasks As New List(Of Task)
tasks.Add(Task.Run(Function()
' This should throw an UnauthorizedAccessException.
Return Directory.GetFiles(path, "*.txt",
SearchOption.AllDirectories)
End Function))
tasks.Add(Task.Run(Function()
If path = "C:\" Then
Throw New ArgumentException("The system root is not a valid path.")
End If
Return { ".txt", ".dll", ".exe", ".bin", ".dat" }
End Function))
tasks.Add(Task.Run(Sub()
Throw New NotImplementedException("This operation has not been implemented.")
End Sub))
Try
Task.WaitAll(tasks.ToArray)
Catch ae As AggregateException
Throw ae.Flatten()
End Try
End Sub
End Module
' The example displays the following output:
' UnauthorizedAccessException:
' Access to the path 'C:\Documents and Settings' is denied.
' ArgumentException:
' The system root is not a valid path.
' NotImplementedException:
' This operation has not been implemented.
Comentarios
Si una tarea tiene una tarea secundaria adjunta que produce una excepción, esa excepción se ajusta en una AggregateException excepción antes de propagarse a la tarea primaria, que ajusta esa excepción en su propia AggregateException excepción antes de propagarla al subproceso que realiza la llamada. En tales casos, la InnerExceptions propiedad de la AggregateException excepción detectada por el Task.Waitmétodo , WaitTask.WaitAny o Task.WaitAll contiene una o varias AggregateException instancias, no las excepciones originales que provocaron el error. Para evitar tener que iterar sobre excepciones anidadas AggregateException , puede usar el Flatten método para quitar todas las excepciones anidadas AggregateException , de modo que la InnerExceptions propiedad del objeto devuelto AggregateException contenga las excepciones originales.
Este método aplana de forma recursiva todas las instancias de AggregateException excepciones que son excepciones internas de la instancia actual AggregateException . Las excepciones internas devueltas en el nuevo AggregateException son la unión de todas las excepciones internas del árbol de excepciones raíz en la instancia actual AggregateException .