Not in the language, no, but you can make your own:
public struct Optional<T>
{
public bool HasValue { get; private set; }
private T value;
public T Value
{
get
{
if (HasValue)
return value;
else
throw new InvalidOperationException();
}
}
public Optional(T value)
{
this.value = value;
HasValue = true;
}
public static explicit operator T(Optional<T> optional)
{
return optional.Value;
}
public static implicit operator Optional<T>(T value)
{
return new Optional<T>(value);
}
public override bool Equals(object obj)
{
if (obj is Optional<T>)
return this.Equals((Optional<T>)obj);
else
return false;
}
public bool Equals(Optional<T> other)
{
if (HasValue && other.HasValue)
return object.Equals(value, other.value);
else
return HasValue == other.HasValue;
}
}
Note that you won’t be able to emulate certain behaviors of Nullable<T>
, such as the ability to box a nullable value with no value to null, rather than a boxed nullable, as it has special compiler support for that (and a some other) behavior.