What is the need of private constructor in C#?

Question

What is the need of private constructor in C#? I got it as a question for a C# test.

Answer 1

I can can recall few usages for it:

• You could use it from a static factory method inside the same class
• You could do some common work inside it and then call it from other contructure
• You could use it to prevent the runtime from adding an empty contructure automatically
• It could be used (although private) from some mocking and ORM tools (like nhibernate)