.Net 4.0 Optimized code for refactoring existing “if” conditions and “is” operator

Question

I have following C# code. It works fine; but the GetDestination() method is cluttered with multiple if conditions by using is operator.

In

Answer 1

you can either use an interface definition or an abstract method / property

with interface:

public interface IDestinationProvider
{
    sting Destination { get; }
}

string GetDestination(Role role)
{
    var provider = role as IDestinationProvider;
    if (provider != null)
        return provider.Destination;
    return "Default";
}

with an abstract base class

abstract class Role 
{ 
    public abstract string GetDestination();
}

class Manager : Role
{
    public virtual string GetDestination() { return "ManagerHomeA"; }
}

string GetDestination(Role role)
{
    return @"\" + role.GetDestination();
}

or with attributes:

[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
public class DestinationAttribute : Attribute
{
    public DestinationAttribute() { this.Path = @"\Home"; }
    public string Path { get; set; }
}

[Destination(Path = @"\ManagerHome")]
public class Manager : Role { }

string GetDestination(Role role)
{
    var destination = role.GetType().GetCustomAttributes(typeof(DestinationAttribute), true).FirstOrDefault();
    if (destination != null)
        return destination.Path;

    return @"\Home";
}