Question

Take this example:

customer.Salary = Convert.ToDecimal(string.Format("{0}! ", Console.ReadLine().ToString()));

(1) Why in C# we need to always put .ToString() to get it right?

(2) Convert.To… Doesn’t it creates overheads unnecessarily?

Further in the below given code: It gives error: “Input string was not in a correct format”, after accepting user input.

    // Main begins program execution.
    public static void Main()
    {
        Customer customer = new Customer();
        // Write to console/get input
        Console.Write("Enter customer's salary: ");
        customer.Salary = Convert.ToDecimal(string.Format("{0}! ", Console.ReadLine().ToString()));
        Console.WriteLine("Salary in class variable is: {0}", customer.Salary.ToString()); 
        Console.Read();
    }

    class Customer
    {
        public Decimal Salary { get; set; }
    }

Here again, either I must use:

string sal =  Convert.ToDecimal(string.Format("{0}! ", Console.ReadLine().ToString()));
customer.Salary = Convert.ToDecimal(sal);

Or, I must change the data type itself in the Customer class.

Can this overhead be avoided with anything in Generics?

Answer 1

1. You do not need to call .ToString().
2. Yes, it does.

You’re trying to write

customer.Salary = Decimal.Parse(Console.ReadLine());

Your current code does the following:

• Console.ReadLine(): Reads a line from the console, returning a String object.
• (...).ToString() Returns the same String object
• string.Format("{0}! ", (...)): Returns a new String object containing the original string followed by !.
• Convert.ToDecimal((...)): Tries to parse that into a Decimal value.
  Since the string ends with !, it fails