Insert Selected item in listbox using Ado.net and stor proc

Question

I create this class method to Enter Selected Items Form CheckboxList to associated resource I use ADO.net & store Proc to insert data can someone help me to improve it and make to so clean instead of my Hacks BTW I use Microsoft Enterprise Lib

public  static void Insert(List<int> listSkills, int rID)
        {
            var connection = ConfigurationManager.ConnectionStrings["SiteSqlServer"]; 
            Database objDB = new SqlDatabase(connection.ConnectionString);
            //int val = 0;
            using (DbCommand cmd = objDB.GetStoredProcCommand("Insert_Skills_Resources"))
            {
                foreach (var s in listSkills)
                {
                    try
                    {
                        objDB.AddInParameter(cmd, "@SkillID", DbType.Int32, s);
                        objDB.AddInParameter(cmd, "@ResourceID", DbType.Int32, rID);

                        objDB.ExecuteNonQuery(cmd);
                        cmd.Parameters.Clear();


                    }
                    catch (Exception ex)
                    {

                        throw ex;

                    }
                }

            } 

Answer 1

If you are using the Enterprise Library it is often better to set up a default connection in the configuration file:

<configuration>
  <configSections>
    <section name="dataConfiguration" 
       type="Microsoft.Practices.EnterpriseLibrary.Data.Configuration.DatabaseSettings,
            Microsoft.Practices.EnterpriseLibrary.Data, Version=5.0.414.0, 
            Culture=neutral, PublicKeyToken=null" 
        requirePermission="false"/>
  </configSections>

  <dataConfiguration defaultDatabase="SiteSqlServer" />

  <!-- Rest of your settings here, including your SiteSqlServer connection string -->
</configuration>

Now you don't need to look up the connection string - you can rely on the Enterprise library to get it for you:

public static void Insert(IEnumerble<int> skills, int resourceId)
{
    // No dependency on SQL anymore - the connection string is found
    // from the dataConfiguration section in your config file. If you change
    // to another (supported) provider, you don't need to change this code.
    Database db = DatabaseFactory.CreateDatabase();

    // Add in your schema to the stored proc name (I've assumed dbo).
    using (var cmd = db.GetStoredProcCommand("dbo.Insert_Skills_Resources"))
    {
        // This method populates the parameters collection of the DbCommand
        // by interrogating the database about the command.
        db.DiscoverParameters(cmd);

        // As the parameters are now known, we can just set the value of 
        // them directly, no need specify direction or type etc.
        cmd.Parameters["ResourceID"].Value = resourceId;

        foreach (var skill in skills)
        {
            cmd.Parameters["SkillID"].Value = skill;
            db.ExecuteNonQuery(cmd);
                    // Don't need to clear the parameters now.
        }
        // <Pointless try catch removed.>
    }
}   

EDIT:

Sorry, it's been a year or more since I used the Enterprise Library I can't remember whether you need the @ at the start of the parameter name or not - it might be cmd.Parameters["@SkillID"].

EDIT 2:

I remembered why I couldn't remember if you need the @ or not (if that makes sense). You do need the @ BUT, you should use the Database.BuildParameterName method to create the parameter in the format the current provider expects - for sql server this is an @ symbol before the parameter name.

This is how you should do it:

cmd.Parameters[db.BuildParameterName("ResourceID")].Value = resourceId;

With this final correction the code is actually ignorant of the provider!

Answer 2

catch (Exception ex)
{
    throw ex;
}

This code doesn't make any sense. If you want to rethrow an exception, use just throw;, so that the stack trace is not reset. But if that's all you do in your catch block, then there is no reason to use try-catch, you should just remove it.