Introduction: WPF (Windows Presentation Foundation) is a graphic framework used in Windows applications to view user interfaces, data, pictures, and movies. We will list WPF Interview Questions here.
WPF Interview Questions
- Give a brief detail about what is WPF?
Answer: Windows Presentation Foundation (WPF) is an acronym for Windows Presentation Foundation. It’s a WPF-based re-invention of a user interface for desktop applications. Apart from simply dropping control measures on “Windows Forms,” as designers have done for years, WPF gives application production an additional boost, such as Rich User Experience, Visual effects, and so much more.
In a nutshell, WPF allows you to do the following:
- Make standard controls and images.
- It’s easy to load and play video and audio folders.
- Smooth graphic artifacts like drop shadows and color gradients are possible.
- Could use common styles to provide such a consistent theme, skin, and design across multiple controls.
- Things, such as forms, controls, and video, can be transformed.
- Possess the ability to build and animate 3D graphics.
- It’s simple to create vector images that grow without aliasing.
Advantages
- Multimedia implementation is tight.
- Freedom in terms of resolution.
- Acceleration on the hardware level.
- What are the various types of controls available in WPF?
Answer: There are four different types of WPF controls:
- Power: – This is the fundamental control in which you can spend most of your time—for example, text boxes, buttons, and so on. Content controls are now independent controls such as buttons, text boxes, icons, and so on. There are no other keys, such as item controls, that can carry other controls. Multiple text input controls, mark controls, and other controls can be found in the Items control.
- Shape: – These controls allow us to construct basic graphic controls such as Ellipse, Line, and Rectangle.
- These measures help to coordinate and place the controls on the panel. Grid, for example, aids in table alignment, while stacking panel aids in horizontally and vertically alignment.
- This control aids in the placement of any XAML material inside it. Whenever we want to add dynamic control to a WPF monitor, we use this method.
- What are Resources in WPF?
Answer: Tools in Windows Presentation Foundation (WPF) make it easy to reuse commonly specified items and values. In WPF, assets allow you to change the properties of several controls at once. A single resource, for example, may be used to set the historic properties on multiple elements in a WPF application.
The simplest way to determine the resource is at the level of the Portal or Page element. Any asset you specify for an element also refers to that element’s child elements. If you specify a resource for just a Window component with a Grid as a child component, the grid component may also use the resource specified for the screen elements. If you specify a resource for the grid component, though, the asset only refers to the grid entity’s child items.
There are 2 types of resources:
- Static Resource
- Dynamic Resource
- What are static and dynamic resources?
Answer: There are two types of resources:
- Static Resource (whose value is determined at the time of loading) and Dynamic Resource (whose price is calculated at the loading point).
- Dynamic Resource – We use Dynamic Asset when we need to adjust the property’s value at initialization.
- What is the difference between a Static Resource and a Dynamic Resource in Windows Presentation Foundation (WPF)?
Answer:
- During the loading of the XAML, which happens until the request is actually run, a Static Resource would be solved and allocated to the land. Any modifications to the resource vocabulary will be ignored since it would only be allocated once.
- While loading, a DynamicResource attributes an Emotion object to the asset. However, the resource is not looked up until runtime, when the Emotion object is asked and for quality. This prevents the resource from being looked up before it is required during runtime. A forward connection to an asset specified later in the XAML is a great example. A resource that does not exist until rendering is yet another example. If the source asset vocabulary changes, it will update the goal.
- What is the Command Design Pattern in WPF?
Answer: Among the most powerful process models in object-oriented data structures is the Command Design Pattern. This design decouples the action request from the entity that currently acts; in other words, a control pattern describes the activity as an object. The functionality to also be implemented is not included in a Control object. This promotes financial flexibility by removing the direct relation between command meanings and functionality. The command pattern is the best pattern to manage the object when you really want to execute operations based on user requests.
The representatives of the Control Design Pattern are as follows:
- Invoker.
- Control.
- Concrete Command.
- Receiver.
- Customer.
- What is XAML and why do we need it in WPF?
Answer: Your WPF UI is represented by an XML file called XAML. Using XML to describe the user interface was to compose it once and run it anywhere. As a result, the same XAML UI can be made as a Personal computer with WPF and presented in the application with a WPF web page or Silverlight application.
- Explain WPF styles.
Answer: WPF styles function similarly to CSS styles in that we define models for a guide and recycle them anywhere we need them in the program. In the very same way, WPF styles allow everyone to define attributes and reuse them in the implementation.
- So is XAML meant only for WPF ?
Answer: No, XAML isn’t just for Windows Presentation Foundation. XAML is an XML-based language with many variations.
- WPF content, such as WPF items, commands, and files, is described using WPF XAML. XPS XAML, which specifies an XML representation of electronic records, is also available in WPF XAML.
- Silverlight XAML is a variant of WPF XAML designed specifically for Silverlight apps. Silverlight is a cross-platform online check for creating rich web content with 2-dimensional graphics, animation, audio, and video.
- The XAML for Windows Workflow Foundation (WWF) allows us to explain the content of the Windows Workflow Framework. The WWF algorithm then takes this XAML and applies it to the application.
- What is a value convertor in WPF?
Answer: A Value Conversion acts as a link between such a target which an origin, and is required when a target is linked to only one source, like when a text box and a button command are used together. Whenever the text in the search box is filled or empty, you want to activate or disable the button control.
You must transform the string data to Boolean in this case. And use a Value Converter. This is feasible. It is necessary to inherit from I Value Convert in the System to achieve Value Converters. Windows are the most common type of computer. Incorporate the 2 techniques, Transform and Convert It, back in the information namespace.
- Can you explain the complete WPF object hierarchy?
Answer:
- Object: Since WPF is built with.NET, the.NET class diagram is the first class that WPF UI classes inherited.
- Dispatcher: This class guarantees that only the thread that owns him has direct access to all WPF UI artifacts. Other connections that do not possess him must use the dispatcher object to communicate with him.
- Dependency: XAML, an XML format, is used to depict WPF UI components. Other WPF entities surround a WPF component at any particular time, and the surrounding entities will influence this component, which is possible thanks to this dependence class. If a panel covers a textbox, that panel’s background color is more likely to be acquired by the text field.
- Visual: This really is the class that aids in the graphic display of WPF UI.
- UI Element: This class aids in the implementation of functions such as events, input, and layouting.
- This class offers support for fabrication, styles, attachment, and tools, among other things.
Finally, all WPF controls such as textboxes, buttons, grids, and anything else you may think of inherit from the foundation element.
- Could you tell me what are the main differences between Style and Control Template?
Answer:
- Styles set control property.
- Most functions have a Control Template attribute that specifies how they can be made.
To give you an example, you could use a design to group situations for several homes so that you really can reuse them to optimize your settings. Styles may be applied to individual controls or all controls of a given kind.
Control Templates may be applied by a style or applied directly to control to alter its appearance. The standard models for all functions are included in the.net WPF gatherings.
- Is WPF based on Windows Forms or is it something entirely different?
Answer:
These are two completely distinct innovations. They do share certain interoperability levels both ways, but otherwise, they are completely different. Since Windows Forms is essentially a minimal layer on top of Win32/MFC, its flexibility in.NET is limited in some cases. WPF is a brand-new UI architecture designed from the ground up.
- WPF is more suitable for cross-platform development in the context of ‘flashy’ user interfaces. It does, however, include a newer version of the.net system than WinForms, as well as a dx9 compliant GPU or lower (which most people will have).
- While WinForms is indeed an advanced technology that can be built faster than WPF, both techniques could be used to accomplish the same task. WinForms is frequently used to create enterprise applications, while WPF is frequently used to build more end-user-focused software, games, and other apps.
- Describe some of the benefits of using WPF instead of Windows types.
Answer: The following are some of the benefits of using WPF rather than Window forms:
- XAML makes it easy to build and edit the GUI, and it divides the job between a designer (XAML) and a developer (C#, VB.NET, and so on).
- It lets you build web applications for both Browsers and internet (Silverlight/XBAP) applications.
- Databinding is a technique that allows you to keep data and design apart.
- For enhanced quality, the GUI is drawn using processing power.
- What is MVVM?
Answer: MVVM (Model View ViewModel) is a WPF application development platform. The MVC architecture is just the same as MVVM. It’s a three-tier construction with an additional layer. MVVM allows for loose coupling.
In 2005, John Gossman implemented MVVM as a concrete implementation of Martin Fowler’s wider Presentation Model pattern to be used with WPF. The MVVM patterns are used to create applications that use various determining structures accessible in some form for WPF, Silverlight Desktop/web, and Browsers.
Advantage of MVVM
- Modularity is a term that is used to demonstrate the ability
- A test-driven methodology is used.
- As views and view models, the UI and business layers are separated.
- Sharing of code among articles and types.
- Easy to keep up with.
List of Features of MVVM
- Like MVP and MVC, it distinguishes the market and presentation levels.
- Enhance the structure and division of interests (View, ViewModel, and Model).
- Improve the Designer/Developer Workflow.
- Simplicity and testability should be improved.
- The comprehensive information binding functionality of XAML makes this possible.
- There’s no need for a code underneath the file (minimalist code-behind file).
- Provides the opportunity to design applications for a variety of environments.
- Data binding, order, validation, and so much more are all available.
- Designers and developers should collaborate.
- What are the Binding Modes in XAML?
Answer: The Data Binding feature specifies the communication path to the source and the data flow directly from the origin. There are 5 ways to connect a data-target object to a source in XAML (WPF, Silverlight, WP, or Win8 App).
- OneWay: Data only travels in one direction; the origin estate changes the target property automatically. However, the original product remains unchanged.
- TwoWay: Data travels in both directions; any changes made in one are immediately changed in another.
- OneWayToSource: Data is moved from the goal to the origin, with changes to the target properties updating the source properties immediately, but the target remains unchanged.
- OneTime: Data is updated once and then never again; adjustments to a source property only adjust the target property the very first time; the origin is not changed, and possible changes have no impact on the target property.
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