Foundations of Programming - Karl Seguin

Chapter 8 - Back to Basics: Exceptions
SqlConnection connection = new SqlConnection(FROM_CONFIGURATION)
SqlCommand command = new SqlCommand("SomeSQL", connection);
connection.Open();
command.ExecuteNonQuery();
command.Dispose();
connection.Dispose();
If ExecuteNonQuery throws an exception, neither our command nor our connection will get disposed
of. The solution is to use Try/Finally:
SqlConnection connection;
SqlCommand command;
try
{
connection = new SqlConnection(FROM_CONFIGURATION)
command = new SqlCommand("SomeSQL", connection);
connection.Open();
command.ExecuteNonQuery();
}
finally
{
if (command != null) { command.Dispose(); }
if (connection != null) { connection.Dispose(); }
}
or the syntactically nicer using statement (which gets compiled to the same try/finally above):
using (SqlConnection connection = new SqlConnection(FROM_CONFIGURATION))
using (SqlCommand command = new SqlCommand("SomeSQL", connection))
{
connection.Open();
command.ExecuteNonQuery();
}
The point is that even if you can't handle an exception, and you should centralize all your logging, you do
need to be mindful of where exceptions can crop up - especially when it comes to classes that
implement IDiposable.
Foundations of Programming Copyright © Karl Seguin www.codebetter.com
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