How to invoke Nullable.GetUnderlyingType on an object? What is the difference between Nullable.GetUnderlyingtype and .GetType

Question

I want to understand usage of Nullable.GetUnderlyingType(). When should it be used?

Also, in the following example, How can we make use of GetUnderlyingType instead of GetType

    int? x = 1;
    Console.WriteLine(x.GetType().Name);

You don't need it, since you know the type of x statically... — Thomas Levesque, Feb 16 '12 at 17:20
My question is for the case where we dont know the type at compile time. x.GetType can throw exception if x is null. — Tilak, Feb 16 '12 at 17:26
When should it be used? When you need to know the underlying type of a nullable! It's also handy to test whether or not *any* arbitrary type is a nullable: `if (Nullable.GetUnderlyingType(typeToTest) != null) { /* typeToTest is nullable */ }` — LukeH, Feb 16 '12 at 17:29
Well after little thought, I understood, it is not possible to have type not known statically, and getting null value. So my comment is invalid. — Tilak, Feb 16 '12 at 17:30

score 0 · Answer 1 · answered Mar 22 '13 at 03:47

Assuming that you have obtained a property of a class via reflection (call it vProp), the following should work:

Type tNullType = Nullable.GetUnderlyingType(vProp.PropertyType);
Type tType = tNullType ?? vProp.PropertyType;

tType will return the actual property type, whether Nullable or not, that you can use for casting or other similar operations.

1 Answers1