Solved

Cleaning up after using an OleDbDataReader

Posted on 2006-07-18
5
464 Views
Last Modified: 2012-06-27
Hi,

I have just been made aware that I need to call Dispose() when using an OleDbCommand.  I now do this in the "finally" block of the code to make sure it gets called when an exception is thrown.  But what about an OleDbDataReader?

Is this code appropriate?

OleDbDataReader driverRuns = dbSelectCommand1.ExecuteReader();             
driverRuns.Close();

If there is an exception in ExecuteReader(), does the Close() need to be called? I assume it's null anyway.  Then what about explicitly setting the OleDbDataReader to null?  This would be something I would also put into the finally block.

driverRuns = null;

Thanks,
Bob
0
Comment
Question by:ba272
  • 2
  • 2
5 Comments
 
LVL 18

Accepted Solution

by:
Ravi Singh earned 300 total points
ID: 17131827
Hi Bob, if all your database related code is within one try catch block then its always good to do a null check on the object in the finally clause (to avoid any runtime null reference exceptions)... if not null then close the reader and dispose it explicitly... this should mark it for garbage collection.

..
OleDbDataReader driverRuns = null;

try
{
     //...
     driverRuns = dbSelectCommand1.ExecuteReader();
     //... use the reader
}
catch (Exception ex)
{
}
finally
{
     if (driverRuns != null)
     {
          driverRuns.Close();
          driverRuns.Dispose();
     }
}
0
 
LVL 25

Assisted Solution

by:dstanley9
dstanley9 earned 200 total points
ID: 17131865
Easiest way to handle this is to use a using block:

using(OleDbDataReader driverRuns = dbSelectCommand1.ExecuteReader())
{
  while(driverRuns.Read())
  {
   
  }
}

This automatically disposes the OleDbDataReader (which closes it) in a finally block without having to explicitly close or dispose of the reader.  Using blocks can be used around Commands and Connections as well.
0
 

Author Comment

by:ba272
ID: 17131972
I will use the "using" statement in the future.  But I have hundreds of uses of these objects and need a quick way to make them as safe as possible, and to prevent memory leaks.

So I like Zephyr's approach for now.  Except I don't find a Dispose() in the OleDbDataReader object.

Am I missing something?

Bob
0
 
LVL 18

Expert Comment

by:Ravi Singh
ID: 17132113
Hi, sorry the data reader doesnt expose the Dipose() method... calling close on the reader should do it
0
 

Author Comment

by:ba272
ID: 17132560
Ok.  No problem.

Thanks.
0

Featured Post

Gigs: Get Your Project Delivered by an Expert

Select from freelancers specializing in everything from database administration to programming, who have proven themselves as experts in their field. Hire the best, collaborate easily, pay securely and get projects done right.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Introduction Although it is an old technology, serial ports are still being used by many hardware manufacturers. If you develop applications in C#, Microsoft .NET framework has SerialPort class to communicate with the serial ports.  I needed to…
It was really hard time for me to get the understanding of Delegates in C#. I went through many websites and articles but I found them very clumsy. After going through those sites, I noted down the points in a easy way so here I am sharing that unde…
Microsoft Active Directory, the widely used IT infrastructure, is known for its high risk of credential theft. The best way to test your Active Directory’s vulnerabilities to pass-the-ticket, pass-the-hash, privilege escalation, and malware attacks …
Established in 1997, Technology Architects has become one of the most reputable technology solutions companies in the country. TA have been providing businesses with cost effective state-of-the-art solutions and unparalleled service that is designed…

786 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question