What's the meaning of public MyException(string str):base (str)

Question

I have got the reply for the below. public class MyException : Exception { public MyException(string str):base (str) { } } But no explanation for public MyException(string str):base (str) .What's its meaning and purpose

denkai · Answer

That is your class constructor. Basically this is what is called when you initialize the class using the new statement for example: MyException ex = new MyException(Something); The base:(str) is a directive that forwards the call to the constructor of the base class. Here is a short example: public class BaseClass { public BaseClass() { Console.WriteLine(BaseClass Initialized); } } public class DerivedClass : BaseClass { pubic DerivedClass() : base() { Console.WriteLine(DerivedClass Initialized); } } Now if you create an instance of the derived class from a console application. DerivedClass x = new DerivedClass(); The console output would be: BaseClass Initialized DerivedClass Initialized Try looking for info on the web about .Net and OO concepts (http://www.developer.com/net/csharp/article.php/1465681). Hope this helps Dominique LeBlond