It depends on the point of view, just having multiple physical files or having both multiple physical files and the method of class construction. Yes, you can use multiple files (header/source) in C++ as you do in C#. However, the C# partial class is constructed more like a C++ class-namespace hybrid where you can define methods and data members in multiple source files that somehow come together in the scope of one class.
"We make a living by what we get, we make a life by what we give." --Winston Churchill