Develop Reference

Any .NET Winforms control which look like this QT's QPushButton?

Is someone know any .NET Winform control which look like this button control?
QPushButton:
http://zetcode.com/gui/csharpqyoto/layoutmanagement/

You have several options here. You aren't specific about exactly which part of the platform you are using, but if using Winforms, you can certainly customize the buttons to some extent.
If you are using WPF, you can pretty much make it look exactly like you want in XAML. Check out Expression Blend.
As #Dimitri put it, the sky is the limit, but you may need to do the leg work.

You can create custom controls according your need and have its reference added to your project. you will have it added to your toolbox that you can use.

If you are refering to a button that is located on this example form:
We currently finishing our own application that has rather similar looking buttons. We did this by using a third party component. Steps are:
We purchased DevExpress.com's WinForms library.
We developed our own DevExpress Skin (with the help of an external screen design guy)
This was a bit of a work and some amount of money but the results look pretty neat.

How can I create/skin a C# UI?

Ive been working on a C# project for a while now and I fell it needs change its look.
I have found a UI kit that I really like, which can be seen below:
http://medialoot.com/item/transparent-ui-kit/
Does anyone know how to do this?
Thanks
EDIT: Im using WinForms
EDIT2: Maybe I should convert over to WPF? Is this doable?

You can subclass most common controls and draw their appearance yourself. However, unless for novelty applications I doubt your users will thank you for doing so.

Your example is a library of controls. For you to have an appearance such as that you'll have to create or acquire a similar library of controls and replace all your controls in your project to get that appearance.
If you want to update colors (background, foreground, etc.) and such you can make a class that recurses through controls and sets the settings using reflection and a switch statement to process each control. Then just run this on each form before you show it. One word of caution about this, some controls don't respect your changes and get overridden with themes from the OS (datetimerpicker being the biggest culprit). You'll also need to consider whether your users will appreciate the extra work put in for color/appearance changes.

If you don't have very good design skill and have a good know how about creating such templates, its better to buy them.
And C# is just a language. You're looking to create templates and skins for either for ASP.NET website/application or for windows forms.

Have a look at DevExpress Skins
If you can afford it.

Dealing with control flexibility

I've a question more about 'Good Programming Practices'.
I have just started a really big project. I'm using WebGui (long story short.. it is WinForms in web) - but it's not important.
I'm creating milions of forms with milions of controls like TextBox, NumericUpDown, DateTimePicker and etc. It might happen, that I will have to change something in behavior of DateTimePicker or appearance. It will be impossible to change it in every control. I want my project to be flexible so I've got an idea..
I do separate custom controls for every type - string, numeric, date, byte.. and within I will put TextBox for example. And on every form I will put not TextBox, but MyTextBox. In fact, that MyTextBox will be just TextBox, but when I change something there, every control will be changed.
Is it good, popular pracitce in programming?

in the case of WPF this can be achieved quite easily using Styles and Templates.
in Winforms this is not possible, therefore I'd say your approach of deriving from the controls and using your own custom controls on the UI is a good practical approach which helps managing changes centrally.
If the controls were created manually in the programme, alternatively you could use a Factory clase(s) and get the Factories to create the controller object rather than just newing up.
But this might not be possible when the UI is created by dragging and dropping controls as the developer has no control over the creation of controls.
Which ever the approach you choose, the fundamental goal should be to centralize the creation logic of the controlls.

Yes, this is perfectly normal programming practice for GUI development, if the standard controls don't satisfy your requirements.
Most developers get 3rd party control suites for the extra flexibility. The benefits in buying far out weigh the benefits in building core controls yourself.
I've worked at a place that did companyTextBox, companyDatePicker and it worked ok. A couple of controls got revamped over .Net versions so these base classed controls required some surgery. Any depreciated controls were left as framework version dependent.
For special things, I do a lot of research into good custom controls on CodeProject, CodePlex, Code.Google.com,etc and implement them into the project I'm working on.
Otherwise use the stock standard controls or the suite of 3rd party controls the company I'm working for use.
My advice is to get a 3rd party suite of controls and make a ton of re-usable user controls based on the 3rd party ones. This way you can build most of the 200 forms by Drag and Dropping the user controls onto the forms. Make each User-Control Implement an Interface with Create,Retrieve,Update & Delete methods for the forms to generically work with your user controls.

Are there no built in C# GUI Layouts?

I'm used to the GUI frameworks in Java as well as the QT GUI framework, and I'm used to the various layout managers. It doesn't seem that C# has any layout managers built in, or am I missing something?
2 Year Later Edit
I just want to point out to any readers of this question that in hind-sight, my question was misplaced. With proper anchoring and docking of child controls, having a need for the layout managers of Java and QT4 is nearly non-existent.

WPF does have layout managers, see:
http://msdn.microsoft.com/en-us/library/ms745058.aspx
If you're coming from a Java background, then the section "Panel Elements and Custom Layout Behaviors" will be of particular interest.

Both WPF and Windows Forms provide layout capabilities (WPF is just much better at it).
You can achieve moderately complex layouts in Windows Forms too by utilizing the Dock and Anchor properties of controls. Personally I learned what can be achieved and how through Petzold's book on WinForms. If you don't have access to that book, read this short article.

chibacity is right, WPF is loaded with layout managers, all of them are very good.
However if you're going down the WinForms route, you're stuck with TableLayoutPanel, FlowLayoutPanel and SplitContainer. As well as the usual manual Panel and GroupBox controls.

No, you are not missing anything.
.NET does not have built in layout managers for Winforms/Webforms/Console development.
Probably because Visual Studio has good designers, obviating the need.
WPF and Silverlight (both using XAML) do have them, though they are not exactly the same as the Java ones.

WPF and Silverlight have different "Panels" that work similar to the layout managers in other languages.

What is the best way to create a wizard in C# 2.0?

I have a winforms application where users will be creating stock items, and a time of creation there are a number of different things that need to happen.
I think the UI for this should probably be a wizard of some kind, but I'm unsure as to the best way to achieve this. I have seen a couple of 3rd party Wizard controls, and I have also seen manual implementations of making panel visible/invisible.
What are the best ways that people have used in the past, that are easy to implement, and also make it easy to add "pages" to the wizard later on if needed?

I know this answer has already been accepted, but I just found a better Wizard control that's free, and of course, since it's on CodeProject, includes the source, so you can modify it if it's not exactly what you want. I'm adding this as an answer for the next person to stumble across this question looking for a good Wizard control.
http://www.codeproject.com/KB/miscctrl/DesignTimeWizard.aspx

Here are a few more resources you should check out:
This DevExpress WinForms control: http://www.devexpress.com/Products/NET/Controls/WinForms/Wizard/
A home-grown wizards framework: http://weblogs.asp.net/justin_rogers/articles/60155.aspx
A wizard framework by Shawn Wildermut part of the Chris Sells's Genghis framework: http://www.sellsbrothers.com/tools/genghis/

Use a tab-control inside a form.
Change back color to "Control" in all tab-pages.
Set "appearance" to flat buttons to get rid of the white border-stuff.
Hide the tabs by sizing the entire control so that the tabs gets pushed up "under" the title bar of the form. If you need other controls (or banner maybe) above the tab-control, then instead hide the tabs with a panel-control or similar.
Childplay to code logic for back/next buttons and very easy to extend with new pages.

Take a look at this article on MSDN about "inductive user interfaces". It describes a framework (and provides the code to download) based on UserControls that give you "navigation" within a form. Perfect for designing wizards.

The easiest way to create a wizard dialog is to use one of the third-party versions available that handle all of the "hard stuff" (the page navigation, UI framework, etc.) for you. The one I like the most is from Divelements; they have both a WinForms and a WPF version.