In VB6, when referencing a .NET component, why do I have to reference the .TLB file?

In V开发者_StackOverflow中文版B6, when referencing a .NET component, why can't I reference the DLL? Why do I have to reference the .TLB file?

VB6 has no mechanism that allows it to call managed code directly (i.e. the .Net component). The .TLB file contains the compiled header information that VB6 "understands", and in turn allows it to call the .Net assembly.