Philosophy of scroll bars

Suppose I want to design my own text editor . simply like notepad. Without using any richtextbox or other controls LIKE EDIT in C++. Main Handle is just a window in C++ or usercontrol in C#. The Question is here for scrolling option , how can I perform scrolling when user is typing. I mean vertical scrolling here . What is Philosophy of works of scroll bars in C++ windows or C# user controls ?

Should I Clear the (Usercontrol or Window) When User reaches to end of (Usercontrol or Window) and then Put caret on start of (Usercontrol or Window) ? What about scrolling with thumb or hand scrolling ? How can I find the Text 开发者_C百科Position which scroll to ?

What is Philosophy of works of scroll bars ...

In short: Do what is least surprising. In your case this means copy whatever scrolling behaviour your users are already familiar with.