Designing and Architecting Blazor Applications

Question 1

Why Blazor instead of the well known javascript frameworks?

Answer 1

Written in c# and razor syntax.
Can leverage existing .net standard nuget packages.
Powerfull tooling.
Fully supported by Microsoft.
Blazor also is likelly to be faster than JS due the fact it runs over web assembly.

Question 2

What does it mean saying that Blazor is make in a “component driven design”?

Answer 2

It means the pages are built using different components. Reusable components.

Question 3

What are the main benefits of Blazor?

Answer 3

Depenendy Injection, Hosting Options, Standarized Packages, Javascript Interop.

Question 4

What is the role of a service in a MVC project?

Answer 4

It sits between the controller and the repository. Useful when some business logic is necessary.

Question 5

When to use parameter dependency injection and when to use constructor dependency injection?

Answer 5

Parameter dependency injection is used for components and the constructor (most common) dependency injection is used for services.

Question 6

How to inject a logger into a blazor component?

Answer 6

By simply add a inject parameter of the type ILogger

Question 7

What is a Blazor circuit?

Answer 7

Is the context of a connection of a user/tab to our blazor server (not applicable to Blazor web assembly).

Question 8

What is a scoped service lifecycle?

Answer 8

It means the same instance of the service will be used along in the same Blazor circuit (aka context)

Question 9

What is a blazor route constraint?

Answer 9

It allows enforcing a specific param type to a route.

Question 10

How can we monitor page changes in the blazor app?

Answer 10

With the LocationChanged event from the RouteManager class

Question 11

What is a razor class library?

Answer 11

Allows creating and consuming common components to achieve re-usability. Can be published as a nuget package.

Question 12

Only UI components can be packed in razor class lib ?

Answer 12

No… also functional libs can be packed into razor comps.

Question 13

How to create a nuget package out of a razor class lib?

Answer 13

By simply selecting “Pack” in visual studio.

Question 14

How to manage user’s state in the app (e.g: grid preferences)?

Answer 14

By using local or session storage.

Question 15

What is the local storage?

Answer 15

It is owned by the browser and it stores all the tabs… non-secure data… good for keeping user preferences like hidden notifications and etc.

Question 16

What is the session storage?

Answer 16

more secure… prevents data be loaded by a different user. scoped to the opened tab, then auto deleted.

Question 17

Are local and session storage truly secure?

Answer 17

No. data is still somehow accessible - mitigated by encryption, but still need to be careful.

Question 18

What is the recommended way to interact with the browser storage?

Answer 18

ProtectedBrowserStorage nuget package.. is still on Alpha. Need to change the host.cshtml to RenderMode.Server and add the js from the nuget package.

Question 19

what is a common automatically generated API documentation?

Answer 19

swashbuckle swagger.

Question 20

What is the correct way of using a HTTPClient in .net core? When was it introduced?

Answer 20

Via HTTPClientFactory. Introduced on .net 2.1

Question 21

How http client can be used?

Answer 21

By typed HTTP clients and client factory directly.

Question 22

how to instantiate a typed http client?

Answer 22

It looks more complicated that it is… all it is needed is a generic Timplementation of tclient… can be done using a simple anonymous method.

Question 23

Does Blazor has its own http client lib?

Answer 23

Yes… it simplifies the unmarshalling.

Question 24

what to do when the api expects key value pairs instead of a json (used to be like this in forms)?

Answer 24

Define a dictionary of the fields, then use link to create a url encoded string. then do the send async.

Question 25

what is fiddler useful for?

Answer 25

To debug web requests in and outside the browser.

Question 26

What to do when the model class gets too big?

Answer 26

The model class should be broken down on sub classes. Then the subclasses can be added to the model itself as non-primitive types.

Question 27

Does the data validation work out-of-the-box with nested classes? What about the persistence?

Answer 27

No. Persistence works fine. Because the default validation is property validation, not the whole model validation.

Question 28

Does Blazor allow custom validations on property and model levels?

Answer 28

Yes. Just inherit from ValidationAttribute and define the classname as the data annotation validation.

Question 29

Does Blazor provide a validation nuget package to handle these nested classes?

Answer 29

Yes. Blazor.DataAnnotations.Validation. Via [ValidateComplexType] attribute.

Question 30

How to create a custom validation for a model object?

Answer 30

By implementing the IValidatableObject.

Question 31

Is Blazor and .net core open source?

Answer 31

Yes. available on github.