Question

I’m sure there was a way to easily create an instance of a class but my search of the great interwebs hasn’t found it. Lets say I have this:

List<LicencedCustomer> leftList = new List<LicencedCustomer>();

leftList.Add(new LicencedCustomer (LMAA_CODE:"1",LICENSE_NUMBER:"1",TRADING_NAME:"Bobs Liquor",STATE:"NSW",POSTCODE:"2261"));

My class looks like the below.

public class LicencedCustomer
{

    public string LMAA_CODE {get; set;}
    public string LICENSE_NUMBER {get; set;}
    public string TRADING_NAME {get; set;}
    public string STATE  {get; set;}
    public string POSTCODE  {get; set;}

    public LicencedCustomer(string LMAA_CODE, string LICENSE_NUMBER, string TRADING_NAME, string STATE, string POSTCODE)
    {
        this.LMAA_CODE = LMAA_CODE;
        this.LICENSE_NUMBER = LICENSE_NUMBER;
        this.TRADING_NAME = TRADING_NAME;
        this.STATE = STATE;
        this.POSTCODE = POSTCODE;
    }

    ...

Without the constructor immediately above, I get an error that the class doesn’t contain a constructor that takes 5 arguments (initially I tried it with the values only and no field names in the List.Add function).

Is there a shortcut that allows assignment to properties on creation, without needing to define the constructor explicitly?

Thanks!

EDIT: Wide ranging curiosity has resulted from the capitalised properties – they are only that way because they’ve been built to reflect the headings of an import file. Not my preferred method!

Answer 1

When you use new ( ) you call a constructor that matches the parameters. If you have no defined constructors you will get an implicit parameter less constructor.

To use the shortcut initializer use something like this.

public class sCls
{
    public int A;
    public string B;

}
static void Main(string[] args)
{
   sCls oCls = new sCls() {A = 4, B = "HI"};
}

Edit

---

From comments if you add a consturctor that takes a paramter you lose the implict paramterless constructor

public class sCls
{
    public sCls(string setB)
    {
        B = setB;
    }
    public int A;
    public string B;

}
static void Main(string[] args)
{
    sCls oCls = new sCls() {A = 4, B = "HI"}; // ERROR  error CS1729: 'csCA.Program.sCls' does not contain a constructor that takes 0 arguments
}

You can also use any constructor with the initializer list

public class sCls
{
    public sCls(string setB)
    {
        B = setB;
    }
    public int A;
    public string B;

}
static void Main(string[] args)
{
    sCls oCls = new sCls("hi") {A = 4, B = "HI"};
}

Remember that in all cases the constructor is called before the initializer list even if it has a parameter less constructor. So base class constructions or anything else that happens in the construction of the object will happen first.

    public class BSE
    {
        public BSE()
        {
            BaseA = "Bob";
        }
        public string BaseA;
    }
    public class sCls :BSE
    {

        public int A;
        public string B;

    }
static void Main(string[] args)
{
        sCls oCls = new sCls() {A = 4, B = "HI" };
        Console.WriteLine("{0}", oCls.BaseA);//Prints Bob
}