It isn't possible with the current design of your code. The reason is, you can not reference 1 field of the object in another field before the object is fully constructed. That is same as why we can't use 1 field value in another while declaring as class level varibales.
However, there are ways you can achieve, what you want to.
Option 1:
const string titleText = "Grooming";
List<Reservations> reservations = new List<Reservations>()
{
new Reservations{title=titleText, className=checkColor(titleText)},
};
private static string checkColor(string title)
{
...
}
Option 2:
class Consumer
{
List<Reservations> reservations = new List<Reservations>()
{
new Reservations{title="Grooming"}
};
}
class Reservations
{
string _title;
public string title
{
get
{
return _title;
}
set
{
_title = value;
className = checkColor(title);
}
}
public string className;
private string checkColor(string title)
{
return "";
}
}