A button is an option through which a user can control to click a provided input to an application. There are several buttons, each with different styles, to maintain the difference between the buttons. We use different buttons for a proper structure for an application and a suitable design. Any user can select a button in three different ways they are:
- By clicking it with a mouse.
- By using a specific tab to enter
- By using arrow keys to move within a group
The working of a button is like this. First, the system provides a button for the keyboard focus. Then the button sends a message to the parent window asking to notify it of the selection. After this, the system sends a message to the button to change its state, and finally, the button will output its new state.
In this article, we got a little idea of what a button is, so now we will learn how to create the button in C++ programming language and some other features and uses of basic buttons on a web application.
Creating a button in C++ programming language:
We use one primary function to create a button: CreateWindow or CreateWindowEx dynamically. To work with this function, we must first learn about all windows controls and have a proper windows user interface programming with C/C++ language pre-installed. Now let us look at an example code below to create a button using the CreateWindow function.
HWND hwndButton = CreateWindow( L"BUTTON", // a predefined class (Unicode) L"OK", // text of button WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON, // Styles 10, // x-axis position 10, // y axis position 100, // width of button 100, // height of button m_hwnd, // main window NULL, // No extrenall links (HINSTANCE)GetWindowLongPtr(m_hwnd, GWLP_HINSTANCE), NULL); // no pointers required
In the above C++ example code, we used a new parameter (m_hwnd). This is used to handle the main window. And the word BS_DEFPUSHBUTTON refers to the style type of the button, where it specifies this button is a default push button. And then, we assigned the size and position values. In this code, we specified the dimensions and position values because we used CW_USEDEFAULT, so this function automatically sets all parameters to zero as default. And with this piece of code, we can create a button on any application required.
Applications of buttons:
- A button can send messages to the main window, and the main window returns a message back to the button. So the main or parent window will send the message to the button through an overlapped window using a function called SendMessage. The application will use the BM_GETCHECK message to retrieve the check status of a radio button.
- Similarly, notifications from a button are sent to the main window as WM_COMMAND or WM_NOTIFY messages. These will reach information about which message is used and the reference for every notification.
- Button color messages are a default color provided by the system, where an application can retrieve default values by identifying the color. It can identify by using a function called GetSysColor, or we set the values by using a function called SetSysColors. And this SetSysColors will affect the whole application, so we should not use this function for the customized buttons in an application.
- There is a default messaging process for the button where the system procedure for the predefined button control window class is. This is a default processing procedure for all messaging buttons, and this will state any Boolean statements given to a button.
- The predefined window procedure will pass all other messages to the function DefWindoeProc for the default message processing.
In this article, we have covered the basics of a button and its purpose of the button. Then we have learned how to create a button in C++ programming language. Then we have discussed on the messaging concepts and protocols of the button, like sending messages to the button, notification messages from the buttons, button color messages, and a few related topics. And with all these concepts, we will get a clear idea of how to use buttons. Where to use buttons? And why should we use the button?