Why i need private constructor in class?

Question

Why i need private constructor in class? Need a seniro with an example. why it is used when it best to used.

Gnanavel Sekar · Answer

https://msdn.microsoft.com/en-us/library/kcfb85a6.aspx http://www.c-sharpcorner.com/forums/what-is-the-use-of-private-constructor-in-c-sharp http://stackoverflow.com/questions/2585836/why-do-we-need-a-private-constructor

Ehsan Sajjad · Answer

The basic purpose of private contructor is to control or restrict the direct object creation of the class from outside of it which means that the calling code cannot create the instance of that class directly, instead the object creation might be controlled by a method in the class which might be keeping track of instances created or most of the times it is useful when implementing Singleton design pattern for any class.

Nitin Sontakke · Answer

There are many examples, but unfortunately, not finding one quickly just now. But assume you want to implement some sort of hierarchical object structure, such as Excel Workbook has Worksheets. Now you want to ensure that no worksheet object should ever exists which has no corresponding workbook object. Now what do you do to enforce such a strict object hierarchy? You just make the constructor of the worksheet class private. No nobody can create a worksheet object on it's own. You then give a AddWorksheet() method to the Workbook class which creates and returns an instance of a Worksheet class. Hope that sort of clarifies.