Page setup, Find, Replace Dialog boxes are not available in Toolbox (Visual Studio) to develop Notepad in C#
what namespaces i have to using? where & how can i find the above mentioned Dialog boxes?
And again OP was asking for on new / save as or dispose functionality.
Edited post Edited due to a vague question.
How to do it programmatically and adding the functionality to make those things work is more complicated and will involve more sub systems.
Step by step guide on creating a "notepad" application
Original Post:
All the information you need on default dialogs in winforms
Create your own programmatically (intro)
Or just create your own using forms.