ErrorEventArgs 类
为 Error 事件提供数据。
**命名空间:**System.IO
**程序集:**System（在 system.dll 中）
语法
声明
Public Class ErrorEventArgs
Inherits EventArgs
用法
Dim instance As ErrorEventArgs
public class ErrorEventArgs : EventArgs
public ref class ErrorEventArgs : public EventArgs
public class ErrorEventArgs extends EventArgs
public class ErrorEventArgs extends EventArgs
备注
ErrorEventArgs 包含导致 Error 事件的 Exception。此类提供检索异常的 GetException 方法。
示例
下面的示例创建 ErrorEventArgs 的新实例，并使用 Exception 对其进行初始化。然后，该示例调用 GetException 来检索 Exception 并显示错误信息。没有与此代码相关联的窗体。
Overloads Public Shared Sub Main(args() As String)
' Creates an exception with an error message.
Dim myException As New Exception("This is an exception test")
' Creates an ErrorEventArgs with the exception.
Dim myErrorEventArgs As New ErrorEventArgs(myException)
' Extracts the exception from the ErrorEventArgs and display it.
Dim myReturnedException As Exception = myErrorEventArgs.GetException()
MessageBox.Show(("The returned exception is: " & myReturnedException.Message))
End Sub 'Main
public static void Main(string[] args) {
// Creates an exception with an error message.
Exception myException= new Exception("This is an exception test");
// Creates an ErrorEventArgs with the exception.
ErrorEventArgs myErrorEventArgs = new ErrorEventArgs(myException);
// Extracts the exception from the ErrorEventArgs and display it.
Exception myReturnedException = myErrorEventArgs.GetException();
MessageBox.Show("The returned exception is: " + myReturnedException.Message);
}
int main()
{
// Creates an exception with an error message.
Exception^ myException = gcnew Exception( "This is an exception test" );
// Creates an ErrorEventArgs with the exception.
ErrorEventArgs^ myErrorEventArgs = gcnew ErrorEventArgs( myException );
// Extracts the exception from the ErrorEventArgs and display it.
Exception^ myReturnedException = myErrorEventArgs->GetException();
MessageBox::Show( String::Concat( "The returned exception is: ", myReturnedException->Message ) );
}
public static void main(String[] args)
{
// Creates an exception with an error message.
Exception myException = new Exception("This is an exception test");
// Creates an ErrorEventArgs with the exception.
ErrorEventArgs myErrorEventArgs = new ErrorEventArgs(myException);
// Extracts the exception from the ErrorEventArgs and display it.
System.Exception myReturnedException =
myErrorEventArgs.GetException();
MessageBox.Show("The returned exception is: "
+ myReturnedException.get_Message());
} //main
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.EventArgs
System.IO.ErrorEventArgs
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
ErrorEventArgs 成员
System.IO 命名空间
ErrorEventHandler
FileSystemWatcher
OnError