Test if a floating point number is an integer

Question

This code works (C# 3)

double d;
if(d == (double)(int)d) ...;

1. Is there a better way to do this?
2. For extraneous reasons I want to

Answer 1

If you are just going to convert it, Mike F / Khoth's answer is good, but doesn't quite answer your question. If you are going to actually test, and it's actually important, I recommend you implement something that includes a margin of error.

For instance, if you are considering money and you want to test for even dollar amounts, you might say (following Khoth's pattern):

if( Math.abs(d - Math.Floor(d + 0.001)) < 0.001)

In other words, take the absolute value of the difference of the value and it's integer representation and ensure that it's small.