What is the smoothest, most appealing syntax you've found for asserting parameter correctness in c#?

Question

A common problem in any language is to assert that parameters sent in to a method meet your requirements, and if they don\'t, to send nice, informative error messages. This

Answer 1

Don't know if this technique transfers from C/C++ to C#, but I've done this with macros:

    #define CHECK_NULL(x)  { (x) != NULL || \
           fprintf(stderr, "The value of %s in %s, line %d is null.\n", \
           #x, __FILENAME__, __LINE__); }