ObjectDisposedException
Class
Definition
The exception that is thrown when an operation is performed on a disposed object.
[System.Runtime.InteropServices.ComVisible(true)]
public class ObjectDisposedException : InvalidOperationException
- Inheritance
- Attributes
Inherited Members
System.Exception
System.Object
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
Disposemethod, 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
Closemethod, and you’re trying to access an instance member that gets or sets the object's state. Often, theClosemethod provides a type's public implementation of the IDisposable.Dispose method.You've called an object's
Disposemethod multiple times. Typically, this doesn’t throw an exception. However, depending on how a type implements IDisposable.Dispose, it may not allow multiple calls toDispose.
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
| ObjectDisposedException(String) |
Initializes a new instance of the ObjectDisposedException class with a string containing the name of the disposed object. |
| ObjectDisposedException(SerializationInfo, StreamingContext) |
Initializes a new instance of the ObjectDisposedException class with serialized data. |
| ObjectDisposedException(String, Exception) |
Initializes a new instance of the ObjectDisposedException class with a specified error message and a reference to the inner exception that is the cause of this exception. |
| ObjectDisposedException(String, String) |
Initializes a new instance of the ObjectDisposedException class with the specified object name and message. |
Properties
| Message |
Gets the message that describes the error. |
| ObjectName |
Gets the name of the disposed object. |
Methods
| GetObjectData(SerializationInfo, StreamingContext) |
Retrieves the SerializationInfo object with the parameter name and additional exception information. |