Microsoft KB Archive/312111

= BUG: Access Violation with ADO Recordset and Connection Objects in .NET Framework =

Article ID: 312111

Article Last Modified on 11/28/2007

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APPLIES TO


 * Microsoft ActiveX Data Objects 2.6
 * Microsoft ActiveX Data Objects 2.7
 * Microsoft .NET Framework 1.0
 * Microsoft .NET Framework 1.1

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This article was previously published under Q312111



Caution ADO and ADO MD have not been fully tested in a Microsoft .NET Framework environment. They may cause intermittent issues, especially in service-based applications or in multithreaded applications. The techniques that are discussed in this article should only be used as a temporary measure during migration to ADO.NET. You should only use these techniques after you have conducted complete testing to make sure that there are no compatibility issues. Any issues that are caused by using ADO or ADO MD in this manner are unsupported. For more information, see the following article in the Microsoft Knowledge Base:

840667 You receive unexpected errors when using ADO and ADO MD in a .NET Framework application



SYMPTOMS
You may encounter an access violation and slower connectivity if you do not explicitly close the ActiveX Data Objects (ADO) Recordset and Connection objects.



CAUSE
If you do not close your objects explicitly, the .NET Framework employs garbage collection while the references still exist. Even if you never use the reference again, an access violation can occur.



RESOLUTION
To resolve this problem, always close the ADO Recordset and Connection objects. For example: Dim cn as ADODB.Connection Dim rs as ADODB.Recordset 'Perform necessary tasks. rs.Close cn.Close



STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.



MORE INFORMATION
When you use an ADO Recordset object (ADODB.Recordset) or an ADO Connection object (ADODB.Connection) with .NET Framework applications, always call the Close method when you finish. This ensures that the underlying connection to the data source is released in a timely manner. This also prevents possible access violations, which can occur because garbage collection reclaims unmanaged ADO objects when existing references still exist. This problem most often occurs with garbage collection when the applications are under stress or high usage.

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