Working with JSON files in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is JSON and why is it commonly used in programming?

JSON (JavaScript Object Notation) is a simple text format to store and exchange data. It is easy for humans to read and write, and easy for machines to parse and generate. It is widely used for data exchange between web servers and clients.

beginner

Which C# class is commonly used to read and write JSON files?

The <code>System.Text.Json.JsonSerializer</code> class is commonly used in C# to convert objects to JSON strings and JSON strings back to objects. It helps read from and write to JSON files easily.

intermediate

How do you read a JSON file into a C# object?

You can read a JSON file by first reading the file content as a string using File.ReadAllText, then use JsonSerializer.Deserialize<T>(jsonString) to convert it into a C# object of type T.

intermediate

How do you write a C# object to a JSON file?

Use JsonSerializer.Serialize(object) to convert the object to a JSON string, then write it to a file using File.WriteAllText. This saves the object data in JSON format.

intermediate

What is the importance of matching C# class structure with JSON data?

The C# class properties must match the JSON keys to correctly convert JSON data to objects and vice versa. If they don't match, data may be lost or cause errors during serialization or deserialization.

Which method reads the entire content of a JSON file as a string in C#?

A File.ReadLine

B File.ReadAllText

C JsonSerializer.Deserialize

D JsonSerializer.Serialize

File.ReadAllText reads the whole file content as a string, which can then be deserialized.

Which class is used to convert JSON strings to C# objects?

A JsonReader

B File

C StreamReader

D JsonSerializer

JsonSerializer provides methods to serialize and deserialize JSON data.

What happens if the C# class property names do not match JSON keys during deserialization?

A Properties with no match are ignored

B Program crashes immediately

C JSON file is deleted

D All data is loaded correctly

Properties without matching JSON keys are ignored, so data may be missing.

How do you save a C# object as a JSON file?

A Serialize object to string, then write string to file

B Use File.ReadAllText

C Use JsonSerializer.Deserialize

D Use Console.WriteLine

You serialize the object to a JSON string and then write that string to a file.

Which namespace must you include to work with JSON serialization in C#?

A System.Net

B System.IO

C System.Text.Json

D System.Collections

System.Text.Json contains the JsonSerializer class for JSON operations.

Explain the steps to read data from a JSON file and convert it into a C# object.

Think about file reading and deserialization.

Describe how to save a C# object into a JSON file.

Focus on serialization and file writing.