Basically, I want something like this:
Dictionary<object, string> dict = new Dictionary<object, string>();
dict.Add(null, "Nothing");
dict.Add(1, "One");
Are there any built into the base class library that allow this? The preceding code will throw an exception at runtime when adding the null key.
Thanks
You could avoid using null and create a special singleton value class that does the same thing. For example:
public sealed class Nothing
{
public static readonly Nothing Value = new Nothing();
private Nothing() {}
}
Dictionary<object, string> dict = new Dictionary<object, string>();
dict.add(Nothing.Value, "Nothing");
dict.add(1, "One");
This approach will fail to work if you intend to make your collection more strongly typed - let's say for example you want the key to be a string. Since string is sealed you can't inherit from it to create a "special value" substitute for null. Your alternatives become a bit more complicated. You could:
As an aside, does your dictionary key really need the key to be object
? This can lead to subtle bugs due to reference equality being used where you may have intended Equals() to be evaluated as the basis for comparison.