ObjectDisposedException ObjectDisposedException ObjectDisposedException ObjectDisposedException Class

Definition

public ref class ObjectDisposedException : InvalidOperationException

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

type ObjectDisposedException = class
    inherit InvalidOperationException

Public Class ObjectDisposedException
Inherits InvalidOperationException

Inheritance

ObjectObjectObjectObject

ExceptionExceptionExceptionException

SystemExceptionSystemExceptionSystemExceptionSystemException

InvalidOperationExceptionInvalidOperationExceptionInvalidOperationExceptionInvalidOperationException

ObjectDisposedExceptionObjectDisposedExceptionObjectDisposedExceptionObjectDisposedException

Attributes

ComVisibleAttribute SerializableAttribute

Examples

The following example demonstrates an error that causes the ObjectDisposedException exception to be thrown.

using namespace System;
using namespace System::IO;
int main()
{
   MemoryStream^ ms = gcnew MemoryStream( 16 );
   ms->Close();
   try
   {
      ms->ReadByte();
   }
   catch ( ObjectDisposedException^ e ) 
   {
      Console::WriteLine( "Caught: {0}", e->Message );
   }

}

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);
      }
   }
}

Imports System
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 'Main
End Class 'ObjectDisposedExceptionTest

This code produces the following output:

Caught:  
  Cannot access a closed Stream.  

Remarks

An ObjectDisposedException is thrown when you try to access a member of an object that implements the IDisposable interface, and that object has been disposed. Typically, this exception is caused by one of the following conditions:

• You've called an object's Dispose method, and you’re trying to access an instance member that gets or sets the object's state. The following example illustrates the ObjectDisposedException that is thrown when you try to reset the frequency of timer notifications after you call the Timer.Dispose method.

  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()
  

  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()
  

• You've called an object's Close method, and you’re trying to access an instance member that gets or sets the object's state. Often, the Close method provides a type's public implementation of the IDisposable.Dispose method.

• You've called an object's Dispose method multiple times. Typically, this doesn’t throw an exception. However, depending on how a type implements IDisposable.Dispose, it may not allow multiple calls to Dispose.

In most cases, this exception results from developer error. Instead of handling the error in a try/catch block, you should correct the error, typically by reinstantiating the object.

Constructors

Properties

Methods

Events

Applies to

See Also

• IDisposable