This is not a simple thing to do: it involves two parts:
1) Get the names of the audio resources
2) Load them into a combobox.
The second is trivial:
The first is where the fun is!
You get to get a list of all resources in your assembly:
string all = System.Reflection.Assembly.GetEntryAssembly().GetManifestResourceNames();
Then, you need to decide if the resource is an audio file or not - it will return a list a of name in the form:
You will have to pick the audio files out of that!