Okay, so I wrote this program out of the exercise of a C# programming book (I'm trying to learn here) and it asks for "Override the ToString() method to return all data members".
Have I done this correctly? Or have I just successfully wrote code that compiles but does nothing. What is the purpose of ToString?
I have spent about 30 minutes looking at other posts on this and havn't figured it out, So I decided to make this.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication297
{
class Program
{
static void Main(string[] args)
{
String name = "Stormtrooper";
Employee s = new Employee(name);
Console.WriteLine("The type of hire is a {0}", s.Name);
Console.WriteLine("The identification number is {0}", s.Number);
Console.WriteLine("The date of hire is {0} ABY", s.Date);
Console.WriteLine("The standard galactic salary is...{0:C}", s.Salary);
}
class Employee
{
private string _name;
private string _number;
private int _date;
private int _salary;
public string Name
{
get
{
return _name;
}
}
public string Number
{
get
{
return _number;
}
}
public int Date
{
get
{
return _date;
}
}
public int Salary
{
get
{
return _salary;
}
}
public Employee(string n)
{
_name = n;
_number = "AA23TK421";
_date = 4;
_salary = 800;
}
}
public override string ToString()
{
return "_name + _number + _date + _salary".ToString();
}
}
}
7 Answers
You are returning a string that just says the phrase _name + _number + _date + _salary.
What you likely wanted to do is build a string using those fields. If you wanted them all mushed together Concat would work, but it would be highly un-readable
public override string ToString()
{
return String.Concat(_name, _number, _date, _salary);
}
However what would be better is to use Format and include labels with the values
public override string ToString()
{
return String.Format("Name:{0}, Number:{1}, Date:{2}, Salary:{3}",_name, _number, _date, _salary);
}
If you are using C# 6 or newer you can use the following cleaner format
public override string ToString()
{
return $"Name:{_name}, Number:{_number}, Date:{_date}, Salary:{_salary}";
}
Which is the exact same logic as the previous String.Format version.
The reason people override the ToString() method is to have a default string representation of your object, usually for display to the user or in a log or console, like this:
Console.WriteLine(yourClassObject);
If you do not override the ToString(), then its default implementation is to return the fully qualified name of your object, like this:
YourNamespace.YourClassName
By changing the inherited implementation (from System.Object), then you can make a nicer (read: prettier) representation, like this:
public override string ToString()
{
return String.Format("This instance of my object has the following: Name = {0}, Number = {1}, Date = {2}, Salary = ${3}", _name, _number, _date, _salary);
}
Rather try something like
public override string ToString()
{
return String.Format("Name : {0}, number {1}, date {2}, salary {3}",_name,_number,_date,_salary);
}
But it neads to be part of the class
so
class Employee
{
private string _name;
private string _number;
private int _date;
private int _salary;
.....
public override string ToString()
{
return String.Format("Name : {0}, number {1}, date {2}, salary {3}",_name,_number,_date,_salary);
}
}
Have a look at String.Format Method
Replaces each format item in a specified string with the text equivalent of a corresponding object's value.
If you are using C# 6 (or later) use the nameof() method for the property names in the string in case the property names change. You can also use the $"" notation instead of using string.Format().
For example:
public override string ToString()
{
return $"{nameof(Name)}: {_name}";
}
You could try to format the output in a nice format. (not tested, though)
public override string ToString()
{
return string.Format("Name: {0} Number: {1:n0} Date: {2:yyyy-MM-dd} Salary: {3:n2}", _name, _number, _date, _salary);
}
there are a lot of purposes overwriting .ToString(), depending on the context. for example,
- some developers like to have nicely formatted object description when doing debug, overwriting .ToString() would allow them to have meaningful description with some identifier (for example, the Id of a object);
- Some developers like to put some serialization code into the ToString() method;
- Some developers even put some debug code into the .ToString() method, though it might not be a good practice.
it really depending on the context of your needs. you may find some good practices to follow online - believe there are plenty of resources online.
Without overiding ToString, if you tried to "get" the string value of an Employee, e.g.
var employee1= new Employee();
Console.WriteLine(employee1);
What you'd get is:
ConsoleApplication1.Program+Employee
Which provides no information at all to help you (or a UI) display relevant information.
I use
return _name + _number + _date + _salary;
Which defaults to string,
or a more verbose
return "Name:" + _name + " Number:" + _number + " etc...";
class Program
{
static void Main( )
{
int Number = 10;
Console.WriteLine(Number.ToString());
Customer cc = new Customer();
cc.FirstName = "Rakibuz";
cc.LastName = "Sultan";
Console.WriteLine(Convert.ToString(cc));
}
}
public class Customer
{
public string FirstName;
public string LastName;
public override string ToString()
{
return FirstName + " " + LastName;
}
}
