Develop Reference

Drawing an absolute line in a window in C#

I have an application on windows with multiline text field on it. I need a way to draw lines on that text field, so you could see both, the letters typed and those lines. I need to do this with C#, but I can use .dll's written in C++.
I've heard something about subclassing where I could overtake render function from a window and adjust something to it, how do I do that with C#?
Or maybe there are simplier ways than that? Please share.

In .NET Framework, you may use WPF and write user control with Canvas and TextBox overlaying - and then make such operations with Dependency Properties tracking

Breaking up an all C# WPF application into XAML for one of its UI controls and C#

This is a broad question, I am aware. However, I have been trying to make a modification in a C# source code to enable a ToolboxControl UI control's right hand border to respond to a mouse drag. In other words make the control size bigger by grabbing the right hand boarder and dragging it to the right. I Have not been successful. So I am thinking if I incorporate a XAML file and create the ToolboxControl in XAML, maybe I would have more control in manipulating the ToolBoxControl.
I dont know how to break up a pure C# WPF code into C# and XAML.
In a nutshell, The problem I am dealing currently is that there is already C# code developed by other developers to perform certain function. I am using the existing C# code but I believe if I move some of the UI functionality from the C# into a XAML file, I would have a better handle on adding some of the needed UI features to the original program.
So you see my problem is I am not starting from scratch. I need to use an existing C# code and break away some UI functionality of it nd put it in a new xaml file. Do you have any ideas about any place that that has been done?
I am looking for any repsonse that leads me to a conversation thread or a sample. In other words I dont know where to start from. any useful guidance is apprecaited and would be marked as an answer.

Check out this article.
At its simplest, you will need to add an invisible (or not) drag handle to the right hand border of your control, then adjust the control size during the drag events raised by that drag handle.
Here is another article showing a similar concept expanded to an entire diagramming system, which includes the resize behavior you mentioned.

You may be able to define a style for what you are trying to accomplish. I wouldn't worry too much about breaking apart the C# from the XAML as that is a nice to have but not nec

How can I implement an interactive tutorial inside an app?

I have C# add-in for Word and would like to implement an interactive tutorial like games usually have. I'd like to somehow highlight (maybe by circling) certain visual elements and display text boxes that describe what the element does. For example, say the add-in is a generic workflow editor. I'd like to show to the user, step by step, what needs to be done by visually selecting elements and explaining what they do and what options (s)he has. My first question is: can this be done in C#? My second question is how? :) I suppose I'd have to get the positions of said visual elements and then draw an image on top but I don't know how that could be done.

I'm a bit disappointed that not even a single member of the Stack Overflow community took the the time to at least give a hint about this. But such is life and I'm just going to share my findings here because I'm certain someone else will benefit from them.
To be able to do an interactive tutorial you need three things:
a method to find where a control is located in terms of screen coordinates
a method to point the user to the control by highlighting it or
surrounding it with a red line for example.
a method to do its default action (ie: click a button).
In other words, the idea is to have some sort of window with text describing a control and some graphical way of indicating the control in the app. Optionally, the window could provide something like a ShowMe button which shows the user how to use the control by taking control of the mouse and keyboard.
This is trivial when the controls are made by yourself and thus have source code access. However, when doing such a thing for a black box app such as Word you can use the Windows IAccessible interface. Searching for that with your favorite search engine will yield everything you need to understand it and use it. IAccessible allows one to do many things but most importantly it can get a control's position and can also do the default action.
Having sorted out these things the next step is to figure out how to graphically point out the control. There are many ways to do this but in my case I chose to surround it with a red rectangle. I did this by creating an invisible, borderless form with an empty red rectangle on it. Having the control's position and size, I had no problems placing the aforesaid form over the control.
So there you have it. I laid out the building blocks that one needs to make an interactive tutorial for any app.

How to accomplish different states of view in WPF Apps

I have an idea for a personal project. And I know one way of accomplishing it in Windows Forms (which I no longer wish to use). Basically I could (in WinForms) just draw everything onto the screen (Form) and then when I need to switch views/states of the application, just redraw the new stuff in the old stuff's place.
But how can we have different states in WPF? Is there a "right" or "proper" way of doing this? Is something like this covered somewhere in the docs?
I'd like to do my own searching, but I have no idea what exactly to look for, and current attempts at finding the right information, so far have yielded no helpful (or even relevant) results.
Any help at all will be greatly appreciated. I am new to WPF, but have been making a lot of progress this past week!
Thank you!
P.S.:
I just thouhght of something. If the solution was to draw what is needed for one screen, and when it is time to display the next screen, just dispose of/hide everything and create/display the new stuff, then how would we get around this? Because we can't/shouldn't change XAML markup at runtime, can/should we? :/

Not sure how you drawn your views/states in WinForms (direct painting on a Graphics object?).
The closest to what you're describing is the VisualStateManager. You can use it to statically define several visual states inside a single XAML and transit between them (using a smooth animation if you want).
If what you've done was show different Forms with Show/ShowDialog(), then the equivalent would be to use different Windows and Show/Hide them.
If you just cleared/added Controls to your form, then you can do just the same in WPF. Most Controls in WPF have a Content or Children property instead of Control.Controls in Forms.

I don't know if I understand what you really want. But here are my thoughts:
You can use several Windows and Show/Hide them accordingly
You can use the Frame/Page functionality in WP (MSDN)
if you really need to you could load your XAML and remove the topmost content in your Window and replace it with the loaded content
You could use the VisualStateGroup functionality to change the appearance of your current window
I think you will be happy with the second solution

What is raw code of textbox

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

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.

Use http://www.red-gate.com/products/reflector/ and see for yourself...

Here is what I think it is doing:
The Raw code behind TextBox or any other Control uses Windows API that is responsible for drawing these controls and provide Handles of these controls for later reference.
Windows has been using different methods to draw it's UI like GDI, GDI+ and sometimes DirectX. I may be wrong and there may be some other techs I forgot to mention.
These controls use each window's WinProc to receive Input Notification and other callbacks that notify these controls when clicked, typed or for example resized.