Question

Hello fellow stackoverflow members!

I’m very new to the C# language transfer from Java, Obj-C.
It looks pretty same as Java, but I have trouble issue in very simple thing.
I have created two individual class files, Class-A and Class-Human.

Specification for Class-A

it contains the static main method declared.And I’ve tried to create the new instance of Class-Human.

public static void main(String args[])
{
      Human human = new Human("Yoon Lee", 99);
      int expected = human.getNetID; //<-gets the error at this moment.
}

Specification for Class-Human

namespace Class-A
{
    public class Human
    {
        public String name;
        public int netId;

        public Human(String name, int netId)
        {
            this.name = name;
            this.netId = netId;
        }
     public int getNetID()
     {
         return netId;
     }
}     

Why can’t copy over into local variable?
The compiler prompts me the error of

'Cannot convert method group of 'getNetID' delegate blah blah'

Thank you.

Answer 1

Change the method-call to:

int expected = human.getNetID();

In C#, method-calls require parantheses () containing a comma-separated list of arguments. In this case, the getNetID method is parameterless; but the empty parantheses are still required to indicate that your intention is to invoke the method (as opposed to, for example, converting the method-group to a delegate-type).

Additionally, as others have pointed out, there is a mismatch betweem the return-type of the method and the variable you’re assigning its value to, which you’re going to have to resolve somehow (change both the field-type and method return-type to int / parse the string as an integer, etc.).

On another note, C# natively supports properties for getter-setter semantics, so the idiomatic way of writing this would be something like:

//hyphens are not valid in identifiers
namespace ClassA
{
    public class Human
    {
        // these properties are publicly gettable but can only be set privately
        public string Name { get; private set; } 
        public int NetId { get; private set; }

        public Human(string name, int netId)
        {
            this.Name = name;
            this.NetId = netId;
        }

        // unlike Java, the entry-point Main method begins with a capital 'M'
        public static void Main(string[] args)
        {
            Human human = new Human("Yoon Lee", 99);
            int expected = human.NetId; // parantheses not required for property-getter
        }

    }
}