InternalBufferOverflowException Classe

Definizione

Eccezione generata quando si verifica un overflow del buffer interno.The exception thrown when the internal buffer overflows.

public ref class InternalBufferOverflowException : SystemException
[System.Serializable]
public class InternalBufferOverflowException : SystemException
type InternalBufferOverflowException = class
    inherit SystemException
Public Class InternalBufferOverflowException
Inherits SystemException
Ereditarietà
InternalBufferOverflowException
Attributi

Esempi

Nell'esempio seguente viene illustrato come creare un oggetto FileSystemWatcher per monitorare le modifiche ai file (crea, Elimina, Rinomina, modifiche) che si verificano su un'unità disco.The following example shows how to create a FileSystemWatcher to monitor file changes (creates, deletes, renames, changes) occurring on a disk drive. Nell'esempio viene inoltre illustrato come ricevere correttamente le notifiche degli errori.The example also shows how to properly receive error notifications.

using System;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        //  Create a FileSystemWatcher to monitor all files on drive C.
        FileSystemWatcher fsw = new FileSystemWatcher("C:\\");

        //  Watch for changes in LastAccess and LastWrite times, and
        //  the renaming of files or directories. 
        fsw.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
            | NotifyFilters.FileName |NotifyFilters.DirectoryName;

        //  Register a handler that gets called when a 
        //  file is created, changed, or deleted.
        fsw.Changed += new FileSystemEventHandler(OnChanged);

        fsw.Created += new FileSystemEventHandler(OnChanged);

        fsw.Deleted += new FileSystemEventHandler(OnChanged);

        //  Register a handler that gets called when a file is renamed.
        fsw.Renamed += new RenamedEventHandler(OnRenamed);

        //  Register a handler that gets called if the 
        //  FileSystemWatcher needs to report an error.
        fsw.Error += new ErrorEventHandler(OnError);

        //  Begin watching.
        fsw.EnableRaisingEvents = true;

        Console.WriteLine("Press \'Enter\' to quit the sample.");
        Console.ReadLine();
    }

    //  This method is called when a file is created, changed, or deleted.
    private static void OnChanged(object source, FileSystemEventArgs e)
    {
        //  Show that a file has been created, changed, or deleted.
        WatcherChangeTypes wct = e.ChangeType;
        Console.WriteLine("File {0} {1}", e.FullPath, wct.ToString());
    }

    //  This method is called when a file is renamed.
    private static void OnRenamed(object source, RenamedEventArgs e)
    {
        //  Show that a file has been renamed.
        WatcherChangeTypes wct = e.ChangeType;
        Console.WriteLine("File {0} {2} to {1}", e.OldFullPath, e.FullPath, wct.ToString());
    }

    //  This method is called when the FileSystemWatcher detects an error.
    private static void OnError(object source, ErrorEventArgs e)
    {
        //  Show that an error has been detected.
        Console.WriteLine("The FileSystemWatcher has detected an error");
        //  Give more information if the error is due to an internal buffer overflow.
        if (e.GetException().GetType() == typeof(InternalBufferOverflowException))
        {
            //  This can happen if Windows is reporting many file system events quickly 
            //  and internal buffer of the  FileSystemWatcher is not large enough to handle this
            //  rate of events. The InternalBufferOverflowException error informs the application
            //  that some of the file system events are being lost.
            Console.WriteLine(("The file system watcher experienced an internal buffer overflow: " + e.GetException().Message));
        }
    }
}
Imports System.IO

Module Module1
    Sub Main()
        ' Create a FileSystemWatcher to monitor all files on drive C.
        Dim fsw As New FileSystemWatcher("C:\")

        ' Watch for changes in LastAccess and LastWrite times, and
        ' the renaming of files or directories. 
        fsw.NotifyFilter = (NotifyFilters.LastAccess Or NotifyFilters.LastWrite _ 
            Or NotifyFilters.FileName Or NotifyFilters.DirectoryName)

        ' Register a handler that gets called when a 
        ' file is created, changed, or deleted.
        AddHandler fsw.Changed, New FileSystemEventHandler(AddressOf OnChanged)

        ' The commented line of code below is a shorthand of the above line.
        ' AddHandler fsw.Changed, AddressOf OnChanged

        ' NOTE: The shorthand version is used in the remainder of this code.
        ' FileSystemEventHandler
        AddHandler fsw.Created, AddressOf OnChanged 
        ' FileSystemEventHandler
        AddHandler fsw.Deleted, AddressOf OnChanged

        ' Register a handler that gets called when a file is renamed.
        ' RenamedEventHandler
        AddHandler fsw.Renamed, AddressOf OnRenamed

        ' Register a handler that gets called if the 
        ' FileSystemWatcher needs to report an error.
        ' ErrorEventHandler
        AddHandler fsw.Error, AddressOf OnError

        ' Begin watching.
        fsw.EnableRaisingEvents = True

        ' Wait for the user to quit the program.
        Console.WriteLine("Press 'Enter' to quit the sample.")
        Console.ReadLine()
    End Sub

    ' This method is called when a file is created, changed, or deleted.
    Private Sub OnChanged(ByVal source As Object, ByVal e As FileSystemEventArgs)

        ' Show that a file has been created, changed, or deleted.
        Dim wct As WatcherChangeTypes = e.ChangeType
        Console.WriteLine("File {0} {1}", e.FullPath, wct.ToString())
    End Sub

    ' This method is called when a file is renamed.
    Private Sub OnRenamed(ByVal source As Object, ByVal e As RenamedEventArgs)

        ' Show that a file has been renamed.
        Dim wct As WatcherChangeTypes = e.ChangeType
        Console.WriteLine("File {0} {2} to {1}", e.OldFullPath, e.FullPath, wct.ToString())
    End Sub

    ' This method is called when the FileSystemWatcher detects an error.
    Private Sub OnError(ByVal source As Object, ByVal e As ErrorEventArgs)

        ' Show that an error has been detected.
        Console.WriteLine("The FileSystemWatcher has detected an error")

        ' Give more information if the error is due to an internal buffer overflow.
        If TypeOf e.GetException Is InternalBufferOverflowException Then
            ' This can happen if Windows is reporting many file system events quickly 
            ' and internal buffer of the  FileSystemWatcher is not large enough to handle this
            ' rate of events. The InternalBufferOverflowException error informs the application
            ' that some of the file system events are being lost.
            Console.WriteLine( _
                "The file system watcher experienced an internal buffer overflow: " _
                + e.GetException.Message)
        End If
    End Sub
End Module

Commenti

In una FileSystemWatcher, quando si riceve la notifica delle modifiche ai file, il sistema archivia tali modifiche in un buffer che il componente crea e passa alle API (Application Programming Interface).In a FileSystemWatcher, when you are notified of file changes, the system stores those changes in a buffer the component creates and passes to the Application Programming Interfaces (APIs). Se sono presenti molte modifiche in un breve periodo di tempo, è possibile che si verifichi un overflow del buffer, causando la generazione di un'eccezione, che comporta la perdita di tutte le modifiche.If there are many changes in a short time, the buffer can easily overflow, resulting in an exception being thrown, which essentially loses all changes. Per evitare l'overflow del buffer, utilizzare le proprietà FileSystemWatcher.NotifyFilter e FileSystemWatcher.IncludeSubdirectories per filtrare le notifiche di modifica indesiderate.To keep the buffer from overflowing, use the FileSystemWatcher.NotifyFilter and FileSystemWatcher.IncludeSubdirectories properties to filter out your unwanted change notifications. È inoltre possibile aumentare la dimensione del buffer interno mediante la proprietà FileSystemWatcher.InternalBufferSize.You can also increase the size of the internal buffer through the FileSystemWatcher.InternalBufferSize property. Tuttavia, l'aumento delle dimensioni del buffer è costoso, quindi il buffer è più piccolo possibile.However, increasing the size of the buffer is expensive, so keep the buffer as small as possible.

Costruttori

InternalBufferOverflowException()

Inizializza una nuova istanza predefinita della classe InternalBufferOverflowException.Initializes a new default instance of the InternalBufferOverflowException class.

InternalBufferOverflowException(SerializationInfo, StreamingContext)

Inizializza una nuova istanza vuota della classe InternalBufferOverflowException che è serializzabile tramite gli oggetti SerializationInfo e StreamingContext specificati.Initializes a new, empty instance of the InternalBufferOverflowException class that is serializable using the specified SerializationInfo and StreamingContext objects.

InternalBufferOverflowException(String)

Inizializza una nuova istanza della classe InternalBufferOverflowException con il messaggio di errore da visualizzare specificato.Initializes a new instance of the InternalBufferOverflowException class with the error message to be displayed specified.

InternalBufferOverflowException(String, Exception)

Inizializza una nuova istanza della classe InternalBufferOverflowException con il messaggio da visualizzare e l'eccezione interna generata specificati.Initializes a new instance of the InternalBufferOverflowException class with the message to be displayed and the generated inner exception specified.

Proprietà

Data

Ottiene una raccolta di coppie chiave/valore che forniscono informazioni definite dall'utente aggiuntive sull'eccezione.Gets a collection of key/value pairs that provide additional user-defined information about the exception.

(Ereditato da Exception)
HelpLink

Ottiene o imposta un collegamento al file della Guida associato all'eccezione.Gets or sets a link to the help file associated with this exception.

(Ereditato da Exception)
HResult

Ottiene o imposta HRESULT, un valore numerico codificato che viene assegnato a un'eccezione specifica.Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.

(Ereditato da Exception)
InnerException

Ottiene l'istanza di Exception che ha causato l'eccezione corrente.Gets the Exception instance that caused the current exception.

(Ereditato da Exception)
Message

Ottiene un messaggio che descrive l'eccezione corrente.Gets a message that describes the current exception.

(Ereditato da Exception)
Source

Ottiene o imposta il nome dell'oggetto o dell'applicazione che ha generato l'errore.Gets or sets the name of the application or the object that causes the error.

(Ereditato da Exception)
StackTrace

Ottiene una rappresentazione di stringa dei frame immediati nello stack di chiamate.Gets a string representation of the immediate frames on the call stack.

(Ereditato da Exception)
TargetSite

Ottiene il metodo che genera l'eccezione corrente.Gets the method that throws the current exception.

(Ereditato da Exception)

Metodi

Equals(Object)

Determina se l'oggetto specificato è uguale all'oggetto corrente.Determines whether the specified object is equal to the current object.

(Ereditato da Object)
GetBaseException()

Quando ne viene eseguito l'override in una classe derivata, restituisce l'Exception che è la causa radice di una o più eccezioni successive.When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.

(Ereditato da Exception)
GetHashCode()

Funge da funzione hash predefinita.Serves as the default hash function.

(Ereditato da Object)
GetObjectData(SerializationInfo, StreamingContext)

Quando ne viene eseguito l'override in una classe derivata, imposta il controllo SerializationInfo con le informazioni sull'eccezione.When overridden in a derived class, sets the SerializationInfo with information about the exception.

(Ereditato da Exception)
GetType()

Ottiene il tipo di runtime dell'istanza corrente.Gets the runtime type of the current instance.

(Ereditato da Exception)
MemberwiseClone()

Crea una copia superficiale dell'oggetto Object corrente.Creates a shallow copy of the current Object.

(Ereditato da Object)
ToString()

Crea e restituisce una rappresentazione di stringa dell'eccezione corrente.Creates and returns a string representation of the current exception.

(Ereditato da Exception)

Eventi

SerializeObjectState

Si verifica quando un'eccezione viene serializzata per creare un oggetto di stato eccezione contenente i dati serializzati relativi all'eccezione.Occurs when an exception is serialized to create an exception state object that contains serialized data about the exception.

(Ereditato da Exception)

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