Question

Take this code sample:

string status = "ok";
SqlCommand cmd=null;
SqlTransaction trans=null;
try
{
    cmd = defs.prepquery("");
    trans = cmd.Connection.BeginTransaction();
    cmd.Transaction = trans;

}
catch (Exception ex)
{
    status = defs.logerror("initalizing sql transaction:" + ex.ToString());
    return status;
}

try
{
    if (oper == "submit")
    {
        cmd.CommandText = "update DCM_Mapping_Sessions set StatusID=2 " + 
            "where MappingSessionID=" + mpsid + "";
        cmd.ExecuteNonQuery();
    }
    else if (oper == "delete")
    {
        // .......etc etc 
    }
    catch(Exception ex2)
    {
        //rollback , close the connection
       // handle the ex 
    }

    // if everything is ok , comit the transaction and close the connection
}

So my question is: What happens with the objects in the try block when an exception occurs ?
Does C# allows me to be lazy and destroys the objects(destroying the pending transaction meaning rollback) and closes the connection if an exception occurs ?

I come from a C\C++ background so i am doing my stuff as above to be safe and not end with a transaction open if an exception occurs somewhere below.

Answer 1

You should be disposing/closing the connection and transaction.

The best way to do so is to wrap the creation in a using statement.

Provides a convenient syntax that ensures the correct use of IDisposable objects.

In essence a using statement wraps the creation of the objects in try{}finally{} blocks to ensure proper disposal.

    using(var cmd = defs.prepquery(""))
    using(var trans = cmd.Connection.BeginTransaction())
    {

    }