ObjectDisposedException 类

定义

public ref class ObjectDisposedException : InvalidOperationException

public class ObjectDisposedException : InvalidOperationException

[System.Serializable]
public class ObjectDisposedException : InvalidOperationException

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class ObjectDisposedException : InvalidOperationException

type ObjectDisposedException = class
    inherit InvalidOperationException

[<System.Serializable>]
type ObjectDisposedException = class
    inherit InvalidOperationException

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type ObjectDisposedException = class
    inherit InvalidOperationException

Public Class ObjectDisposedException
Inherits InvalidOperationException

继承

Object

Exception

InvalidOperationException

ObjectDisposedException

继承

Object

Exception

SystemException

InvalidOperationException

ObjectDisposedException

属性

SerializableAttribute ComVisibleAttribute

示例

下面的示例演示了导致 ObjectDisposedException 引发异常的错误。

using System;
using System.IO;

public class ObjectDisposedExceptionTest
{
   public static void Main()
   {
      MemoryStream ms = new MemoryStream(16);
      ms.Close();
      try
      {
         ms.ReadByte();
      }
      catch (ObjectDisposedException e)
      {
         Console.WriteLine("Caught: {0}", e.Message);
      }
   }
}

open System
open System.IO

let ms = new MemoryStream 16
ms.Close()
try
    ms.ReadByte()
    |> ignore
with :? ObjectDisposedException as e ->
   printfn $"Caught: {e.Message}"

Imports System.IO

Public Class ObjectDisposedExceptionTest
   
   Public Shared Sub Main()
      Dim ms As New MemoryStream(16)
      ms.Close()
      Try
         ms.ReadByte()
      Catch e As ObjectDisposedException
         Console.WriteLine("Caught: {0}", e.Message)
      End Try
   End Sub
End Class

此代码生成以下输出：

Caught:
  Cannot access a closed Stream.

注解

尝试访问实现IDisposable接口或IAsyncDisposable接口的对象的成员以及该对象已被释放时，将引发 anObjectDisposedException。 通常，此异常由以下条件之一引起：

• 你已调用对象的IDisposable方法（或IDisposableAsync对象DisposeDisposeAsync的方法），并且你正在尝试访问获取或设置对象的状态的实例成员。 下面的示例演示 ObjectDisposedException 了调用该方法后尝试重置计时器通知的频率时 Timer.Dispose 引发的。

  using System;
  using System.Threading;
  
  public class Example
  {
     public static void Main()
     {
        Timer t = new Timer(TimerNotification, null,
                           100, Timeout.Infinite);
        Thread.Sleep(2000);
        t.Dispose();
  
        t.Change(200, 1000);
        Thread.Sleep(3000);
     }
  
     private static void TimerNotification(Object obj)
     {
        Console.WriteLine("Timer event fired at {0:F}", DateTime.Now);
     }
  }
  // The example displays output like the following:
  //    Timer event fired at Monday, July 14, 2014 11:54:08 AM
  //
  //    Unhandled Exception: System.ObjectDisposedException: Cannot access a disposed object.
  //       at System.Threading.TimerQueueTimer.Change(UInt32 dueTime, UInt32 period)
  //       at Example.Main()
  

  open System
  open System.Threading
  
  let timerNotification _ =
      printfn $"Timer event fired at {DateTime.Now:F}"
  
  let t = new Timer(timerNotification, null, 100, Timeout.Infinite)
  Thread.Sleep 2000
  t.Dispose()
  
  t.Change(200, 1000)
  |> ignore
  Thread.Sleep 3000
  
  // The example displays output like the following:
  //    Timer event fired at Monday, July 14, 2014 11:54:08 AM
  //
  //    Unhandled Exception: System.ObjectDisposedException: Cannot access a disposed object.
  //       at System.Threading.TimerQueueTimer.Change(UInt32 dueTime, UInt32 period)
  //       at <StartupCode$fs>.main()
  

  Imports System.Threading
  
  Module Example
     Public Sub Main()
        Dim t As New Timer(AddressOf TimerNotification, Nothing, 
                           100, Timeout.Infinite)
        Thread.Sleep(2000)
        t.Dispose()
        
        t.Change(200, 1000)                   
        Thread.Sleep(3000)
     End Sub
  
     Private Sub TimerNotification(obj As Object)
        Console.WriteLine("Timer event fired at {0:F}", Date.Now)
     End Sub
  End Module
  ' The example displays output like the following:
  '    Timer event fired at Monday, July 14, 2014 11:54:08 AM
  '    
  '    Unhandled Exception: System.ObjectDisposedException: Cannot access a disposed object.
  '       at System.Threading.TimerQueueTimer.Change(UInt32 dueTime, UInt32 period)
  '       at Example.Main()
  

• 你已调用对象的 Close 方法，并且正在尝试访问获取或设置对象的状态的实例成员。 通常，该方法 Close 提供该方法的类型的公共实现 IDisposable.Dispose 。 这同样适用于 CloseAsync 和 <xref:System.IAsyncDisposable.DisposeAsync*?displayProperty=nameWithType>。

• 已多次调用对象的 Dispose 或 DisposeAsync 方法。 通常，这不会引发异常。 但是，根据类型实现 IDisposable.Dispose 方式， IAsyncDisposable.DisposeAsync或者它可能不允许对该方法进行多次调用。

在大多数情况下，此异常由开发人员错误导致。 通常，应该通过重新验证对象来更正错误，而不是在块中 try/catch 处理错误。

另请参阅

• IDisposable