Exception handling important for the following code

Question

I have copied the following code from here and here. I want to know is exception handling required for the following code ? What hapens if an exception is thrown before the DB connection is closed, so i think that its important to have a try-catch here.

Please give your opinion?

using System; 
using System.Data; 
using System.Data.SqlClient; 


class OutputParams 
{ 
    [STAThread] 
    static void Main(string[] args) 
    { 

    using( SqlConnection cn = new SqlConnection("server=(local);Database=Northwind;user id=sa;password=;")) 
    { 
        SqlCommand cmd = new SqlCommand("CustOrderOne", cn); 
        cmd.CommandType=CommandType.StoredProcedure ; 

        SqlParameter parm= new SqlParameter("@CustomerID",SqlDbType.NChar) ; 
        parm.Value="ALFKI"; 
        parm.Direction =ParameterDirection.Input ; 
        cmd.Parameters.Add(parm); 

        SqlParameter parm2= new SqlParameter("@ProductName",SqlDbType.VarChar); 
        parm2.Size=50; 
        parm2.Direction=ParameterDirection.Output; 
        cmd.Parameters.Add(parm2); 

        SqlParameter parm3=new SqlParameter("@Quantity",SqlDbType.Int); 
        parm3.Direction=ParameterDirection.Output; 
        cmd.Parameters.Add(parm3);

        cn.Open(); 
        cmd.ExecuteNonQuery(); 
        cn.Close(); 

        Console.WriteLine(cmd.Parameters["@ProductName"].Value); 
        Console.WriteLine(cmd.Parameters["@Quantity"].Value.ToString());
        Console.ReadLine(); 
    } 
}

codeandcloud · Accepted Answer · 2013-05-26 16:15:17Z

2

The using directive is expanded as try...finally so it makes sense to nest that inside a try... catch block.

P.S: there is no need to use cn.Close() as finally block essentially does that.

answered May 26, 2013 at 16:15

codeandcloud

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5 Comments

Sharon Watinsan Over a year ago

So, you mean that a try-catch block is required, and i can close the connection inside the finally clause ?

codeandcloud Over a year ago

please see this link: stackoverflow.com/questions/13082590/…

Matthew Watson Over a year ago

@sharonHwk You don't need try/catch/finally. Just use using and don't call cn.Close().

Sharon Watinsan Over a year ago

@MatthewWatson what hapence if there's an exception. How will i know what caused it if we aren't having a catch block here ?

Matthew Watson Over a year ago

@sharonHwk Normally exceptions should be caught at a higher level. The higher level code can catch exceptions and log them or whatever. You should only catch an exception if you know how to respond to it. Of course if this is your main program method then it is the right place, but it looks like test code to me.

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