Zealogics Interview Questions and Answers

convert.ToString is a static method that converts a specified value to its equivalent string representation, while ToString is an instance method that returns a string representation of the object.

• convert.ToString is a static method in the Convert class, while ToString is an instance method in the Object class.

• convert.ToString can handle null values and return an empty string, while ToString will throw a NullReferenceE...read more

Encapsulation is the concept of bundling data and methods that operate on the data into a single unit, while abstraction is the concept of hiding the implementation details and showing only the necessary features of an object.

• Encapsulation involves bundling data and methods into a single unit (class), protecting the data from outside interference.

• Abstraction involves hiding the implementation details and showing only t...read more

A delegate in C# is a type that represents references to methods with a specific parameter list and return type.

• Delegates allow methods to be passed as parameters to other methods.

• Delegates can be used to define callback methods.

• Delegates are similar to function pointers in C++.

• Example: delegate int MathOperation(int x, int y);

• Example: MathOperation add = (a, b) => a + b;

OOPS concepts in C# include encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (class).

• Inheritance: Allows a class to inherit properties and behavior from another class.

• Polymorphism: Ability to present the same interface for different data types.

• Abstraction: Hiding the complex implementation details and showing only the necessar...read more

Interface is a contract with no implementation, while abstract class can have some implementation.

• Interface cannot have any implementation, only method signatures.

• Abstract class can have both abstract methods and concrete methods.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Interfaces are used to achieve multiple inheritance in Java.

• Example: interface Animal { void eat(); } abs...read more

Static class is a class that cannot be instantiated and is used for grouping related methods and properties. Singleton class is a class that can only have one instance and provides a global point of access to it.

• Static class cannot be instantiated, while singleton class can have only one instance.

• Static class is used for grouping related methods and properties, while singleton class provides a global point of access to...read more

An optional parameter is a parameter in a function or method that does not have to be provided by the caller.

• Optional parameters are used to provide default values or allow the caller to omit certain arguments.

• They are typically defined with a default value in the function signature.

• Example: function greet(name, greeting = 'Hello') { console.log(`${greeting}, ${name}!`); }

Strings in C# are immutable to ensure data integrity and thread safety.

• Immutable strings prevent accidental data modification, ensuring data integrity.

• To resolve immutability, use StringBuilder class for mutable string operations.

• Example: StringBuilder sb = new StringBuilder("Hello"); sb.Append(" World");

Triggers in WPF are used to apply changes to UI elements based on certain conditions or events.

• Triggers can be used to change the appearance of a control based on user interaction or data changes.

• There are different types of triggers in WPF such as EventTrigger, DataTrigger, and MultiTrigger.

• Example: Using a DataTrigger to change the background color of a button based on a binding value.

Dependency property in WPF is a specialized type of property that extends the functionality of a regular property.

• Dependency properties support features like data binding, styles, templates, and animations.

• They enable property value inheritance, change notification, and validation.

• Example: DependencyProperty.Register() method is used to create a dependency property.

Dependency injection is a design pattern that allows a program to achieve Inversion of Control by injecting dependencies into a class.

• Promotes loose coupling between classes, making code easier to manage and test.

• Facilitates unit testing by allowing mock dependencies to be injected.

• Commonly used in frameworks like Spring (Java) and Angular (JavaScript).

• Example: Instead of a class creating its own dependencies, they are...read more

Data binding in WPF allows synchronization of data between UI elements and data sources.

• WPF supports four types of data binding: one-way, two-way, one-time, and one-way-to-source.

• Data binding can be done in XAML using the Binding markup extension.

• You can also use data binding in code-behind using the Binding class.

• Data binding can be used to bind UI elements to properties of objects, collections, XML data, etc.

icommand is used for executing commands in interactive mode in the .NET framework.

• Enables interactive command line execution in .NET applications

• Provides a way to execute commands and receive output in real-time

• Useful for creating interactive console applications

MVVM is a design pattern that separates the user interface from the business logic and data model.

• MVVM stands for Model-View-ViewModel

• Model represents the data and business logic

• View represents the UI components

• ViewModel acts as an intermediary between the Model and View

• ViewModel exposes data and commands to the View

Establishing connection between view and viewmodel involves data binding and communication mechanisms.

• Use data binding frameworks like Angular's ngModel or React's setState to bind data between view and viewmodel

• Implement event handling to communicate user interactions from view to viewmodel

• Utilize two-way data binding to automatically update the view when the viewmodel changes

• Use observables or reactive programming to...read more

A dispatcher is a software component that receives requests and sends them to the appropriate service or resource.

• Responsible for routing requests to the correct destination

• Coordinates communication between different components

• Can prioritize and schedule tasks based on predefined rules

A value converter in WPF is used to convert data from one type to another for binding purposes.

• Converts data between different types for data binding

• Implements the IValueConverter interface in WPF

• Can be used to format data for display in UI elements

• Example: converting a boolean value to a visibility enum for showing/hiding elements

Constructors initialize objects, while destructors clean up resources before an object is destroyed.

• A constructor is a special method called when an object is instantiated.

• Example: `class MyClass { public: MyClass() { /* initialization code */ } };`

• A destructor is called when an object goes out of scope or is deleted.

• Example: `class MyClass { public: ~MyClass() { /* cleanup code */ } };`

• Constructors can be overloaded t...read more

Dependency property in WPF is a specialized type of property that extends the CLR property system.

• Dependency properties support features like data binding, styles, templates, and animations.

• They enable property value inheritance, change notification, coercion, and validation.

• Example: DependencyProperty.Register() method is used to create a new dependency property.

Data template defines the structure of data, while control template defines the appearance and behavior of a control.

• Data template specifies the data fields and their types, while control template specifies the layout and styling of a control.

• Data template is used to bind data to controls, while control template is used to define the visual representation of a control.

• Examples: Data template for a list of products may ...read more

Func is a delegate that can return a value, while Action is a delegate that does not return a value.

• Func can return a value, while Action cannot

• Func has a return type specified, while Action does not

• Example: Func square = x => x * x; Action print = x => Console.WriteLine(x);