Single file for all interfaces or one file per interface definition?
Balena & Dimauro’s of book of ‘Pratical Guidelines’ advocates a single file called Interfaces.vb/cs to hold all interface definitions. Their aim is to minimise the proliferation of small files, where each holds a single interface definition.
I can see benefits to both approaches. Does anyone have any strong views or experience that strongly supports one approach?
I would say, its better to have them in a separate file specially if your solution is in source control. If you have multiple check outs disabled in your source control then only one developer can work on one file/interface. Also you can compare what has been checked in against each interface, instead of looking at the difference of files.
If you have a interface which is only implemented in one class, then I would rather have both of them in a same file.