Someone told me recently that Direct X was only compatible with Visual C++ compiler and I was just wondering if that was true. would it work with Dev-C++?

You can use DirectX with DevCpp.

For completeness, DirectX is itself language agnostic. It is built on top of COM, which makes it somewhat available to any language that supports COM interfaces. C++ provides the best COM support, as Visual Basic has a number of limitations that require wrapper controls to be written in C++ to expose COM objects to VB from time to time. That said, DirectX can be used from C++, VB, Java, Python and a plethora of other languages.

Given the above, it thus becomes obvious that not only do you not need a specific compiler, such as Visual C++, to use DirectX, but you don't need any particular language. (Good luck using DirectX from, say, Ruby, though, as I doubt a COM interface library exists.)

I used to use DirectX with Dev-C++, and it worked quite well, but sometimes I ran into problems that were very frustrating and hard to solve. I found that you can download the free Microsoft Visual C++ Toolkit, Microsoft Platform SDK, and Code::Blocks IDE. If you use the Visual C++ Toolkit's compiler, linker, etc... in Code::Blocks, you have a fairly similar interface to Dev-C++, and you are pretty much using the Visual C++ compiler. I still use this, and although I have run into a few problems, they are much easier to solve than the ones I had with Dev-C++.

Hope this helps.