What is Blazor in ASP.NET?
a) A library for server-side development
b) A framework for building interactive web UIs
c) A tool for database management
d) A language for front-end development
Answer: b) A framework for building interactive web UIs
Which Blazor hosting model runs the application on the client-side?
a) Blazor Server
b) Blazor WebAssembly
c) Blazor Desktop
d) Blazor Cloud
Answer: b) Blazor WebAssembly
What does the @page directive do in a Blazor component?
a) Defines a route for the component
b) Specifies the data-binding context
c) Sets the layout for the component
d) Imports a namespace
Answer: a) Defines a route for the component
In Blazor, what is the purpose of the @code block?
a) To define CSS styles
b) To write inline JavaScript
c) To write C# code in a Razor component
d) To configure routing
Answer: c) To write C# code in a Razor component
Which method is used to handle form submissions in Blazor?
a) OnSubmit
b) OnClick
c) OnChange
d) OnValidSubmit
Answer: d) OnValidSubmit
What is the default file extension for a Blazor component?
a) .cshtml
b) .razor
c) .html
d) .cs
Answer: b) .razor
Which Blazor component lifecycle method is called when the component is first initialized?
a) OnInit
b) OnInitialized
c) OnParametersSet
d) OnAfterRender
Answer: b) OnInitialized
How can you pass parameters to a Blazor component?
a) Using URL parameters
b) Using @parameter directives
c) Using attributes in the component tag
d) Using HTTP POST requests
Answer: c) Using attributes in the component tag
What is the purpose of the @inject directive in Blazor?
a) To inject services into a component
b) To create a new component instance
c) To define component routing
d) To include JavaScript libraries
Answer: a) To inject services into a component
Which method is used to perform asynchronous data loading in Blazor?
a) OnInitialized
b) OnInitializedAsync
c) OnAfterRender
d) OnAfterRenderAsync
Answer: b) OnInitializedAsync
What type of binding is used to bind a form input to a property in Blazor?
a) Event binding
b) Two-way binding
c) One-way binding
d) Data binding
Answer: b) Two-way binding
In Blazor, how do you define a route for a component?
a) Using the Route attribute
b) Using the @page directive
c) Configuring routes in Startup.cs
d) Declaring routes in appsettings.json
Answer: b) Using the @page directive
What is the purpose of the @layout directive in a Blazor component?
a) To specify a layout component for the page
b) To define CSS styles for the component
c) To configure the data context
d) To handle component routing
Answer: a) To specify a layout component for the page
What is the purpose of the StateHasChanged method in Blazor?
a) To update the UI after data changes
b) To trigger a re-render of the component
c) To call a server-side API
d) To initialize component state
Answer: b) To trigger a re-render of the component
Which of the following is NOT a valid Blazor component event handler?
a) OnClick
b) OnChange
c) OnSubmit
d) OnRender
Answer: d) OnRender
What is the primary purpose of the HttpClient service in Blazor?
a) To manage client-side state
b) To perform HTTP requests to APIs
c) To handle user input
d) To render components
Answer: b) To perform HTTP requests to APIs
How do you access a service registered in the dependency injection container in Blazor?
a) By using @service directive
b) By injecting it into the component constructor
c) By calling GetService method
d) By using the @inject directive
Answer: d) By using the @inject directive
What is the role of RenderFragment in Blazor?
a) To define a component’s layout
b) To hold a piece of UI that can be rendered
c) To configure component routing
d) To manage component state
Answer: b) To hold a piece of UI that can be rendered
Which Blazor component lifecycle method is called after the component has rendered?
a) OnInitialized
b) OnParametersSet
c) OnAfterRender
d) OnInitializedAsync
Answer: c) OnAfterRender
How do you perform navigation programmatically in Blazor?
a) Using the NavigateTo method of NavigationManager
b) Using @route directive
c) Using HttpClient
d) By modifying the href attribute of a link
Answer: a) Using the NavigateTo method of NavigationManager
Which directive is used to include another Razor component in a Blazor page?
a) @include
b) @component
c) @using
d) @page
Answer: c) @using
What does the OnParametersSet lifecycle method do in a Blazor component?
a) Initializes component state
b) Handles parameter changes
c) Performs asynchronous operations
d) Renders the component
Answer: b) Handles parameter changes
What is the purpose of EventCallback in Blazor?
a) To handle component events
b) To bind data to UI components
c) To define routes for components
d) To inject services
Answer: a) To handle component events
How can you handle form validation in Blazor?
a) By using ValidationMessage component
b) By creating custom validators
c) By using data annotations and DataAnnotationsValidator
d) By configuring validation in Startup.cs
Answer: c) By using data annotations and DataAnnotationsValidator
What is the role of CascadingParameter in Blazor?
a) To pass parameters to nested components
b) To define global styles
c) To manage component state
d) To configure routing
Answer: a) To pass parameters to nested components
How do you define a custom component in Blazor?
a) By creating a new .html file
b) By creating a new .cs file
c) By creating a .razor file with C# code
d) By configuring it in Startup.cs
Answer: c) By creating a .razor file with C# code
Which Blazor directive is used to specify a component’s layout?
a) @page
b) @layout
c) @model
d) @using
Answer: b) @layout
What is the purpose of the OnAfterRenderAsync method in Blazor?
a) To handle asynchronous operations after the component has rendered
b) To initialize component state
c) To update UI elements synchronously
d) To handle parameter changes
Answer: a) To handle asynchronous operations after the component has rendered
How do you set a default value for a parameter in a Blazor component?
a) By specifying the value in the constructor
b) By setting the value in the @code block
c) By using the default keyword
d) By defining a default parameter in the component tag
Answer: b) By setting the value in the @code block
What is the purpose of @bind in Blazor?
a) To bind a component to a service
b) To create a one-way data binding
c) To create a two-way data binding for form inputs
d) To define a route
Answer: c) To create a two-way data binding for form inputs
How can you pass a value from a parent component to a child component in Blazor?
a) By using a parameter attribute
b) By using a cascading parameter
c) By setting a property in the parent’s constructor
d) By using a static field
Answer: a) By using a parameter attribute
What does the OnInitialized lifecycle method do in Blazor?
a) Initializes component parameters
b) Performs component rendering
c) Initializes component state
d) Handles form submissions
Answer: c) Initializes component state
What is the use of RenderMode in Blazor Server-Side?
a) To define the rendering strategy for components
b) To configure the client-side JavaScript
c) To manage server-side state
d) To specify the hosting environment
Answer: a) To define the rendering strategy for components
Which component is used to display validation messages in Blazor?
a) ValidationMessage
b) ErrorDisplay
c) FormValidator
d) DataError
Answer: a) ValidationMessage
How do you perform data binding for a select element in Blazor?
a) Using @bind directive with a select element
b) Using @foreach to generate options
c) Using @data directive
d) By setting properties in the @code block
Answer: a) Using @bind directive with a select element
What is the purpose of @onchange in a Blazor component?
a) To define a CSS style
b) To handle change events for form inputs
c) To specify a layout
d) To configure routing
Answer: b) To handle change events for form inputs
How can you use JavaScript interop in Blazor?
a) By using @inject directive
b) By defining JavaScript functions in wwwroot and calling them using IJSRuntime
c) By adding JavaScript directly to .razor files
d) By configuring JavaScript libraries in Startup.cs
Answer: b) By defining JavaScript functions in wwwroot and calling them using IJSRuntime
What does IJSRuntime interface provide in Blazor?
a) Methods to interact with JavaScript from .NET code
b) Methods to manage server-side state
c) Methods for component rendering
d) Methods for dependency injection
Answer: a) Methods to interact with JavaScript from .NET code
What is the role of the OnParametersSetAsync lifecycle method in Blazor?
a) To handle asynchronous operations after parameters have been set
b) To initialize component state
c) To update UI elements
d) To configure routing
Answer: a) To handle asynchronous operations after parameters have been set
How do you dynamically load a component in Blazor?
a) Using ComponentLoader service
b) By using DynamicComponent class
c) By creating a new instance of the component manually
d) By using @bind directive
Answer: b) By using DynamicComponent class
What is the purpose of @key directive in Blazor?
a) To define a unique key for rendering lists
b) To encrypt data before rendering
c) To specify the layout of a component
d) To handle component parameters
Answer: a) To define a unique key for rendering lists
How do you handle user input validation in Blazor?
a) Using ValidationSummary component
b) Using data annotations and DataAnnotationsValidator
c) By defining custom validation functions in @code block
d) By configuring validation in Startup.cs
Answer: b) Using data annotations and DataAnnotationsValidator
What is the purpose of OnAfterRender lifecycle method in Blazor?
a) To perform actions after the component has rendered
b) To initialize component state
c) To handle parameter changes
d) To configure routing
Answer: a) To perform actions after the component has rendered
How do you define a route parameter in Blazor?
a) By using @parameter directive
b) By defining parameters in the URL within the @page directive
c) By creating query strings
d) By configuring routes in Startup.cs
Answer: b) By defining parameters in the URL within the @page directive
Which Blazor lifecycle method is called when a component’s parameters are set?
a) OnInitialized
b) OnParametersSet
c) OnAfterRender
d) OnInitializedAsync
Answer: b) OnParametersSet
What is the use of the @functions directive in Blazor?
a) To define C# functions within a Razor component
b) To declare component styles
c) To configure routing
d) To manage JavaScript interop
Answer: a) To define C# functions within a Razor component
How can you use dependency injection in Blazor?
a) By using @inject directive in Razor components
b) By creating services in Startup.cs
c) By manually passing dependencies to components
d) By configuring services in appsettings.json
Answer: a) By using @inject directive in Razor components
What does the OnInitializedAsync lifecycle method do in Blazor?
a) Initializes component state asynchronously
b) Handles form submissions
c) Updates UI elements
d) Configures routing
Answer: a) Initializes component state asynchronously
How do you handle navigation events in Blazor?
a) Using NavigationManager service
b) By modifying the URL directly
c) By configuring routes in Startup.cs
d) By using JavaScript interop
Answer: a) Using NavigationManager service
What is the function of @using directive in Blazor?
a) To include namespaces in a Razor component
b) To define component parameters
c) To specify layout
d) To manage JavaScript interop
Answer: a) To include namespaces in a Razor component
Which Blazor component is used to create a form?
a) EditForm
b) Form
c) InputForm
d) SubmitForm
Answer: a) EditForm
How do you define a template in Blazor?
a) By using the Template directive
b) By creating a new .razor file
c) By defining RenderFragment
d) By specifying the template in Startup.cs
Answer: c) By defining RenderFragment
What is IServiceProvider used for in Blazor?
a) To resolve and provide services to components
b) To handle component rendering
c) To manage JavaScript interop
d) To define component routes
Answer: a) To resolve and provide services to components