Interview questions for .Net Winforms developer

1. What is a Windows Form?

Windows Forms is an API that exists in the Microsoft .NET framework to develop rich client applications. This API lies within the Microsoft .NET stack and gives interfaces to extend the API abstract classes or implement the interfaces to develop rich client applications. Windows Forms is a form of managed libraries in the .NET framework. It provides graphics API and provides more security within the client applications.

2. What are the steps involved in the life cycle of a Windows Form?

These are the basic WinForms Interview Questions asked in an interview. The different steps involved in a Windows Form are –
• Load: This is the first step when a specific form is loaded into the application.
• Activate: This step will come into the picture when the form is highlighted or if it gets focused by getting back from minimized state or if it is loaded for the first time.
• Deactivate: This step will be fired if the form is not focused or if it is closed or minimized, or if it is moved to the background.
• Closing: This step will be triggered if the application is about to be closed, which means just before the step of Closed.
• Closed: This step will be executed when the application is closed.
• Disposed of: This step is executed once after the Form or Application is closed to perform the garbage collection mechanism.

3. What are the different components present in Windows Forms?

There are different Windows Forms API components to develop rich client applications based on different functional requirements. They are TextBoxes, List Boxes, Labels, Controls etc.,
Example:
If there is any kind of login page in an application, the entire login page will be treated as a Windows Forms, and the different components in the Windows Form, i.e. login page, are text fields controls, login button control, and label controls. The text field control captures the data from the user and validates it, and the Button Control performs a set of action after clicking it by validating the text strings given by the user. The label controls will define the text field to be entered, and it helps the user log into the application.

4. What are memory-mapped files used for in .NET?

Memory-mapped files in .NET are used to instantiate the contents of a logical file into the address of the application. This helps a user run processes simultaneously on a single machine and have the data shared between processes.
The MemoryMappedFile.CreateFromFiles() function is used to obtain a memory-mapped file object easily.

5. What is the meaning of CAS in .NET?

CAS stands for Code Access Security. It is vital in the prevention of unauthorized access to programs and resources in the runtime. It can provide limited access to code to perform only certain operations rather than providing all at a given point in time. CAS forms to be a part of the native .NET security architecture.

6. What is the meaning of garbage collection?

Garbage collection is a process that is used to maintain various aspects of memory to prevent memory leaks during program execution.
An entity called the garbage collector is used to allocate and deallocate memory as and when required by an application. This is done by performing checks on the references of variables and objects used by the application. If an object is no longer required by the application, the memory is deallocated and freed up.

7. How are the different background operations carried out in Windows Form?

The different types of background operations carried out by Windows Forms are as below:
• Using different threads for different interfaces in Visual Studio.
• Longtime running operations that cause delay will be performed in the background by using the different forms.
1. How can you save the desired properties of Windows Forms application?
2. .config files in .NET are supported through the API to allow storing and retrieving information. They are nothing more than simple XML files, sort of like what .ini files were before for Win32 apps.

8. How’s anchoring different from docking?

Anchoring treats the component as having the absolute size and adjusts its location relative to the parent form. Docking treats the component location as absolute and disregards the component size. So if a status bar must always be at the bottom no matter what, use docking. If a button should be on the top right, but change its position with the form being resized, use anchoring.

9. How do you retrieve the customized properties of a .NET application from XML .config file?

Initialize an instance of AppSettingsReader class. Call the GetValue method of AppSettingsReader class, passing in the name of the property and the type expected. Assign the result to the appropriate variable.

10. Can you automate this process?

In Visual Studio yes, use Dynamic Properties for automatic .config creation, storage and retrieval. My progress bar freezes up and dialog window shows blank, when an intensive background process takes over.
Yes, you should’ve multi-threaded your GUI, with taskbar and main form being one thread, and the background process being the other.

11. What’s the safest way to deploy a Windows Forms app?

Web deployment: the user always downloads the latest version of the code; the program runs within security sandbox, properly written app will not require additional security privileges.

12. Why is it not a good idea to insert code into InitializeComponent method when working with Visual Studio?

The designer will likely throw it away; most of the code inside InitializeComponent is auto-generated.

13. What are the different functionalities and applications of the Windows Form?

The different functionalities that can be performed using Windows Form are as below:
• To build rich client applications.
• To develop rich and interactive user interfaces.
• To create event handlers.
• To develop different kinds of panels within the window.
• To create Graphical User Interfaces or Graphics forms.
• To display and manage the data submitted by the user.
• To perform data binding operations.

leave your comment


Your email address will not be published. Required fields are marked *