A C# programmer rewrote a Delphi 6 program (no GUI, just files-in-files-out grinding, about 50 procedures and functions totaling less than 1200 lines == 57kb keystrokes) that lives as a single .DPR file.
He delivered a project containing 58 files (52 of them .CS files) in 13 folders nested to various degrees, totaling over 330kb.
Is that typical of C# projects? What strategy do C# programmers typically use to decide how to chop up and organize their project?
It’s more an artifact of the developer using Visual Studio IDE (VS) rather than an issue of C#/.NET itself. The tendancy, when using VS tools, is to put each class in its own .cs file because the Solution Explorer window shows files/folders in a tree-like structure allowing the programmer to visually target their classes quickly.
Also the Visual Studio Add New Item dialog encourages a one-class-per-file approach by generating a new file each time you add a Class to your project.
The namespace hierarchy of a program is usually mimicked using directory folders in Solution Explorer (although it’s not required to match) but this is just another visual quickie.
Example:

(source: spaanjaars.com)
If the programmer were to work outside of the Visual Studio environment you’d likely have much less diarrhea on your hands. Ewww…