CODEWITHSUNDEEP
c#
Potatosaurus
Potatosaurus

Reputation: 475

Invisible constructors, despite use of public access modifier?

I wrote a class with multiple overloads, however when I attempt to utilise them outside the class, only the default constructor can be used. Otherwise I receive an error stating that no such constructor exists.

        public Module()//default Module Class
        {
            Code = "Undefined";
            Title = "Undefined";
            Credits = 0;
            Mark = 0;
            ExamWeighting = 0;
            ExamMark = 0;
            CourseWorkNumber = 1;
            Term = "AY";
            CourseWork1Name = "Undefined";
            CourseWork1Type = "Undefined";
            CourseWork1Weight = 1;
            CourseWork1Mark = 0;
        }

        public Module(string code, string title, int credits, string moduleTerm, double exWeight, double exMark, string cW1Name, string cW1Type, double cW1Weight, double cW1Mark)
        {
            Code = code;
            Title = title;
            Credits= credits;
            Mark = 0;
            ExamWeighting = exWeight;
            ExamMark = exMark;
            CourseWorkWeight = 1.0 - exWeight;
            CourseWorkNumber = 1;
            Term = moduleTerm;
            CourseWork1Name = cW1Name;
            CourseWork1Type = cW1Type;
            CourseWork1Weight = cW1Weight;
            CourseWork1Mark = cW1Mark;

        }

I ensured that I had the correct number and type of parameters, unless of course I'm missing something.

                    string code = tempArray[0];
                    string title = tempArray[1];
                    int credits = Convert.ToInt16(tempArray[2]);
                    string moduleTerm = tempArray[3];
                    double exWeight = Convert.ToDouble(tempArray[4]);
                    double exMark = Convert.ToDouble(tempArray[5]);
                    string cW1Name = tempArray[10];
                    string cW1Type = tempArray[11];
                    double cW1Weight = Convert.ToDouble(tempArray[12]);
                    double cW1Mark = Convert.ToDouble(tempArray[13]);


                    // (string code, string title, int credits, string moduleTerm, double exWeight, double exMark, string cW1Name, string cW1Type, double cW1Weight, double cW1Mark)
                    tempModule = new Module(code, title, credits, moduleTerm, exWeight, exMark, cW1Name, cW1Type, cW1Weight, cW1Mark);

Upvotes: 0

Views: 64

Answers (1)

spender
spender

Reputation: 120496

Having a parameter list a mile long is an anti-pattern. You've just discovered why this is the case by messing up the call, because either you've:

  • got the wrong number of parameters

or

  • got incorrect types in the parameters you're using

at the call site.

If it is inevitable that you need a large number of parameters, then you might consider using an options class that encapsulates all these parameters. This allows for sensible defaults too. So

public class ModuleOptions
{
    public ModuleOptions()
    {
        //supply sensible defaults here
        Code = "Not set";
        Title = "Not set";
        //etc
    }
    public string Code{get;set;}
    public string Title{get;set;}
    //etc...
}

then

public class Module
{
    public Module(ModuleOptions options)
    {
        this.Code = options.Code;
        //etc...
    }
}

So now your call site looks like

var opts = new ModuleOptions
    {
        Code = "1234",
        //etc
    };
var module = new Module(opts);

Now it's a lot easier to see what's happening and you're far less likely to screw up your call.

Upvotes: 1

Related Questions