What's wrong with this C# connection?

[Arielle]

Please tell me what's wrong with this picture.

 
public class MyClass
    {
        SqlConnection       ConnectionSql = null;
        SqlCommand          CommandSql = null;
        SqlDataReader         QueryResult = null;
 
        public MyClass(string dbString)
        {
            ConnectionSql = new SqlConnection(dbString);
            CommandSql = ConnectionSql.CreateCommand();
            CommandSql.Connection = ConnectionSql;
        }
 
 

public string ReturnSomething (string sql, int colIndex)
{
ConnectionSql.O pen();
CommandSql.Comm andText = sql;
CommandSql.Conn ection = ConnectionSql;
QueryResult = CommandSql.Exec uteReader();
return (QueryResult[colIndex].ToString());
}
}