C# initializing struct w/incomplete parameters + formula

Question

Im sure this is simple but I've looked at it too long and I need an answer soon. I am new to C#. If I put GetCommission() within the struct I get

error CS0188: The 'this' object cannot be used before all of its fields are assigned to

outside the struct

error CS0038: Cannot access a non-static member of outer type 'Ex5._3.CommissionForm' via nested type 'Ex5._3.CommissionForm.salespersonFigures'

How do I get this done? Caveat: part of the assignment was that the commission be calculated in a method. None of the struct tutorials I've found deal with assigning one member based on the value of another. It should be kosher as the calculations only use static data. Right?

// Declare class variables and constants
private const decimal WEEKLY_BASE_SALARY = 250m;
private const decimal WEEKLY_QUOTA = 1000m;
private const decimal COMMISSION_RATE = .15m;

public struct salespersonFigures
{
    // Fields
    private string salesperson;
    private decimal weeklySales;
    private decimal commission;
    private decimal pay;

    // Constructor
    public salespersonFigures(string name, decimal sales)
    {
        salesperson = name;
        weeklySales = sales;
        commission = GetCommission(sales);  // error occurs at this line
        pay = WEEKLY_BASE_SALARY + commission;
    }

    // Property

    public decimal Sales
    {
        get
        {
            return weeklySales;
        }
        set
        {
            weeklySales = value;
        }
    }

    public string Name
    {
        get
        {
            return salesperson;
        }
        set
        {
            salesperson = value;
        }
    }

    // Method

    public decimal GetCommission(decimal sales)
    {
        if (sales > WEEKLY_QUOTA)
            return sales * COMMISSION_RATE;
        else return 0m;
    }
}

Answer 1

The constructor:

// Constructor
public salespersonFigures(string name, decimal sales)
{
    salesperson = name;
    weeklySales = sales;
    commission = GetCommission(sales);
    pay = WEEKLY_BASE_SALARY + commission;
}

Is being interpreted as:

// Constructor
public salespersonFigures(string name, decimal sales)
{
    this.salesperson = name;
    this.weeklySales = sales;
    this.commission = this.GetCommission(sales);
    this.pay = WEEKLY_BASE_SALARY + this.commission;
}

So, the problems you could be encountering could be resolved by doing two things:

// Constructor
public salespersonFigures(string name, decimal sales)
{
    salesperson = name;
    weeklySales = sales;
    var tempCommission = GetCommission(sales);
    commission = tempCommission
    pay = WEEKLY_BASE_SALARY + tempCommission;
}

And make the GetCommission method static

Answer 2

Do you really need commision field?

private decimal commission;

You can delete it and have you method in a struct. And I think you don't need sales parameter in yout GetComission method.

Answer 3

Very simple workaround / hack:

public salespersonFigures(string name, decimal sales)
{
      salesperson = name;
      weeklySales = sales;
      // initialize pay and commission
      pay = 0m;
      commission = 0m;
      commission = GetCommission(sales);
      pay = WEEKLY_BASE SALARY + commission;
}

And you do not need the else part of the clause in getCommission, just do this:

public decimal GetCommission(decimal sales)
{
    if (sales > WEEKLY_QUOTA)
        return sales*COMMISSION_RATE;
    return 0m;
}

One more thing, why are you using decimal? You should probably use double's or float's instead, because more methods rely upon float's and doubles's and converting between can be costly

Answer 4

Why not just make GetCommission() into a property: Commission.

There is no need to store commission as a field, it should be a query against the SalespersonFigures object