InternalBufferOverflowException 类

内部缓冲区溢出时引发的异常。

**命名空间:**System.IO
**程序集:**System（在 system.dll 中）

语法

声明
<SerializableAttribute> _
Public Class InternalBufferOverflowException
    Inherits SystemException
用法
Dim instance As InternalBufferOverflowException

[SerializableAttribute] 
public class InternalBufferOverflowException : SystemException

[SerializableAttribute] 
public ref class InternalBufferOverflowException : public SystemException

/** @attribute SerializableAttribute() */ 
public class InternalBufferOverflowException extends SystemException

SerializableAttribute 
public class InternalBufferOverflowException extends SystemException

备注

在 FileSystemWatcher 中，当通知您发生文件更改时，系统将这些更改存储在组件创建并传递给应用程序编程接口 (API) 的缓冲区中。如果短时间内有很多更改，缓冲区容易发生溢出，这样导致引发异常，而实质上会丢失所有更改。为防止缓冲区溢出，请使用 FileSystemWatcher.NotifyFilter 和 FileSystemWatcher.IncludeSubdirectories 属性筛选掉不想要的更改通知。也可以通过 FileSystemWatcher.InternalBufferSize 属性增加内部缓冲区的大小。但是，增加缓冲区大小的成本较大，所以将缓冲区保持得越小越好。

示例

下面的示例演示如何创建 FileSystemWatcher，以监视磁盘驱动器上文件的改动（创建、删除、重命名和更改）。此示例还演示如何正确接收错误通知。

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

继承层次结构

System.Object
   System.Exception
     System.SystemException
      System.IO.InternalBufferOverflowException

线程安全

此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。

平台

Windows 98、Windows 2000 SP4、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

InternalBufferOverflowException 成员
System.IO 命名空间
FileSystemEventArgs 类
FileSystemEventHandler 委托
FileSystemWatcher 类
FileSystemWatcher.IncludeSubdirectories 属性
FileSystemWatcher.InternalBufferSize 属性
FileSystemWatcher.NotifyFilter 属性
NotifyFilters
RenamedEventArgs
RenamedEventHandler
WaitForChangedResult
WatcherChangeTypes