object to struct with as operator

Why does the first one work but not the second one? Is there anything to worry about, when converting objects to structs?

struct Hex { /* ... */ }
object actionData = GetData();

1:

bool isHex = actionData is Hex;
Hex hexx = (Hex)actionData;

2:

Hex hex = actionData as Hex;

>Solution :

Because as operator returns null if type check fails:

The expression of the form E as T
where E is an expression that returns a value and T is the name of a type or a type parameter, produces the same result as: E is T ? (T)(E) : (T)null except that E is only evaluated once.

Which can’t be done if T is non-nullable value type (so compiler emits the error). Using nullable value type as T will work:

object actionData = new Hex(); // your code returning boxed Hex
Hex? hex = actionData as Hex?;
if(hex.HasValue)
{
   ...
}