Question about exception handling

Dave

Hi,

The prevailing wisdom for coding try/catch statements around db connections seems to be as follows:

conn = new MySqlConnection();
cmdGetDate = new MySqlCommand();

try
{
    conn.ConnectionString = connStringSQL;
    conn.Open();

    ...do some stuff
}
catch (Exception dbErr)
{
    throw new Exception(dbErr.Message);
}
finally
{
    conn.Close();
    cmdGetDate.Dispose();
    conn.Dispose();
}

My question is, what if an exception occurs on closing the connection (which is inside the finally part of the try/catch)?

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Dave18y ago
As I understand it, using is just syntactic sugar for the block that I set out above. So, the connection does get closed and disposed, but in a finally block. So, the same query applies.

Also, the 'behind-the-scenes' try/catch stuff in a using block does not actually let you catch any exceptions that are thrown. You need to nest it in an external try/catch:
try{
using{}
}
catch{}
The cost of this being the overhead of 2 try/catch statements. (Pretend in my example above that I did not throw a new exception, but handled the one that was thrown).

Let me know if I have this wrong.
Scott Lysle18y ago
You can use "Using" in the declaration of the connection; when this goes of scope or fails it will dispose of the connection.

using (SqlConnection conn = new SqlConnection(ConnString))

{

conn.Open();

....

}