What is raw code of textbox

Question

May be i can get some negative points on this question but, really this question is boggling in my mind from last many days that what is the basic/raw code behind textbox(or other such controls).

i mean i understands that, we can inherit the textbox class and make our changes, we creates its object and use it.

but wants to know how that class creates a textbox(the design which allow us to enter text) (same query for other components), is it a code of 'C' language which are generating it using CG (computer graphics) programming or any other thing.

Experts please resolve my curiosity.

Thanks

Answer 1

Windows provides several basic API's for drawing on the screen. You can draw pixels, lines, boxes and more complex geometric shapes. There are also API's to draw text. Other API's allow you to react to user input, e.g. mouse movement and clicks and keyboard input.

From these basic API's you can create your own text box by drawing the exact pixels of how the text box should look and react to user input. However, Windows has a built-in concept of a text box. This text box has a standard look and feel and is also integrated with UI concepts like focus, tab order, the clipboard and the caret. But behind the scenes Windows is using the low level API functions to draw on the screen and react to user input.

When you create a TextBox in Windows Forms it actually creates and wraps a standard Windows Edit control. This control is drawn using GDI. However, other programming models like WPF may create TextBox controls that looks like a normal text box but uses a custom implementation supplied by WPF and is drawn using DirectX.