Question

I have string which I create like:

string label = Name + " " + Number;

where Name and Number are properties. I want this label string to change whenever the Name or Number is updated. I tried to use the ref keyword but C# tells me that I can’t use ref for properties. Is there a way to achieve this ?

Answer 1

Create it as another property, with only a get method:

public string Label { get { return Name + " " + Number; }}

This way, every time you call the property it will create the return value based on the current values of Name and Number.

This needs to be defined at a class level though, and Label is probably not an appropriate name either.

---

Of course, the question now is, why call it Label in the first place?

If you are using this value to set a WinForms style label control, and you want to update that dynamically then you will need a different approach. you could modify your current properties for Name and Number to do a “little extra work” in the setters.

For example:

private string _name
public string Name 
{
    get { return _name; }
    set { _name = value; DoChange(); }
}

private string _number
public string Number 
{
    get { return _number; }
    set { _number = value; DoChange(); }
}

public string Label { get { return Name + " " + Number; }}

private void DoChange()
{
    MyLabel.Text = Label;
}

This might be overkill for this question, but just something to think about.