what kind of inheritance is this?

Hi: Now I fully understand it , thank you so much.

Hi Exactly, the specified (if not specified, the default constructor) base class constructor will be called first , then the constructor in the derived class. This will not work with the methods. I think what you are using is to override a base class method. Define in your base class: public virtual void MyMethod(string s) { // ... do some stuff. } Then use the override keyword in the derived class: public override void MyMethod(string s) { // ... do some otherstuff. // maybe you wannt to call the base class method. base.MyMethod(...); } Cheers Simon

sorry , I made some misstake in my last reply. I wrote : public void myMethod(string s): base(string s){} should be : public void myMethod(string s): base.myMethod(string s){}

Hi I think I understand what you are talking about. But if I has implemented my constructor, will the program call the constructor of base class first, then call the code in my construstor later? and can I use this idea in method? for example: public void myMethod(string s): base(string s){} thanks alot for ur help.

Hi No. It means that your the constructor of the derived class calls a constructor of its base class. Classes inherit methods, properties etc. from its base class. But a method of a class cannot inherit from base classes. Sorry, i did not found it in msdn... sometimes it is not easy to find something in msdn. Simon

hi, thank you for ur reply , do you mean that my constructor inherits the base constructor? do you know where can I find the reference in MSDN? thank you.

Hi public MyOwnCustomException (string message) : base(message) {} A derived class can call a constructor of it's base class (with : base(...)). If no base class constructor is called explicit, the default base class constructor will be called. CHeers Simon