Mock File.Exists method in Unit Test (C#)

Possible Duplicate:
.NET file system wrapper library

I would like to write a test where the content of a file get's loaded. In the example the class which is used to load the content is

FileClass

and the method

GetContentFromFile(string path).

Is there any way to mock the

File.exists(string path)

method in the given example with moq?

Example:

I have a class with a method like that:

public class FileClass 
{
   public string GetContentFromFile(string path)
   {
       if (File.exists(path))
       {
           //Do some more logic in here...
       }
   }
}