ErrorEventArgs Class
Provides data for the Error event.
Assembly: System (in System.dll)
The ErrorEventArgs type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetException | Gets the Exception that represents the error that occurred. |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
ErrorEventArgs contains the Exception that caused the Error event. This class provides the GetException method to retrieve the exception.
The following example creates a new instance of ErrorEventArgs and initializes it with an Exception. Then the example calls GetException to retrieve the Exception and display the error message. There is no form associated with this code.
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
The following example shows how to create a FileSystemWatcher to monitor file changes (creates, deletes, renames, changes) occurring on a disk drive. The example also shows how to properly receive error notifications.
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
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
