Question

I am trying to understand DbConnection and DbCommand, and the proper way to dispose those objects after use.

Following is the code snippet I have.
By using “using statement” on DbConnection and DbCommand, would it be sufficient? I am trying to prevent possible memory leak.

2nd question,

Do I have to Dispose DbCommand object?

thanks a lot

DbProviderFactory fac = DbProviderFactories.GetFactory(this.DatabaseProviderName);

using (DbConnection dbConn = fac.CreateConnection())
{
     dbConn.ConnectionString = this.ConnectionString;

     using (DbCommand comm = fac.CreateCommand())
     {
          comm.CommandText = "select * from aTable";
          comm.Connection = dbConn;
          DataTable targetTable = new DataTable();

          DbDataAdapter facDA = fac.CreateDataAdapter();
          facDA.SelectCommand = comm;
          facDA.Fill(targetTable);

          //assuming Adapter would open / close connection (right assumption?)

          //do something with the datatable
     }
}

Answer 1

using using is the same as a try/finally block with dispose() called in finally.

DbCommand should be wrapped in a using statement as it implements IDisposable.

Note that DbCommand is actually an abstract class so you will need to either

• derive from it
• code to an interface (IDbCommand)
• use one of the predefined derived classes such as SqlCommand.

DbConnection is also an abstract class so you will need to do something similar as I have suggested above for DbCommand for this too.

The general recommendation is that if an object implements IDisposable, it should be wrapped in a using statement such that Dispose() is called to free resources, even if an Exception is thrown within in the statement block. In your example then, a good practice would be to wrap each of the connection, command, DataTable and DbDataAdapter objects in a using statement.