NJsonSchema Documentation

You can generate TypeScript code using NJsonSchema.CodeGeneration. You can control the output style using TypeScriptGeneratorSettings.

Interface Style

Set TypeStyle = TypeScriptTypeStyle.Interface to generate TypeScript interfaces.

Class Style

Set TypeStyle = TypeScriptTypeStyle.Class to generate TypeScript classes that implement corresponding interfaces, including methods like init(), fromJS(), and toJSON().

NJsonSchema is distributed via NuGet. Depending on your requirements, you can install the core library or specialized packages for annotations, YAML support, or code generation:

• NJsonSchema: Core JSON Schema parsing, validation, and generation.
• NJsonSchema.Annotations: JSON Schema annotations for controlling serialization.
• NJsonSchema.Yaml: Support for reading and writing JSON Schemas in YAML format.
• NJsonSchema.CodeGeneration: Base classes for generating code from a JSON Schema.
• NJsonSchema.CodeGeneration.CSharp: Generates C# classes from a schema.
• NJsonSchema.CodeGeneration.TypeScript: Generates TypeScript interfaces or classes from a schema.

You can generate a JSON Schema from an existing .NET class using the JsonSchema.FromType<T>() method. This uses reflection and supports various attributes and annotations to define schema constraints like [Required] or [Range].

var schema = JsonSchema.FromType<Person>();
var schemaData = schema.ToJson();

To generate a JSON Schema compatible with the OpenAPI specification instead of the standard JSON Schema spec, configure the SchemaType property in SampleJsonSchemaGeneratorSettings to SchemaType.OpenApi3.

var generator = new SampleJsonSchemaGenerator(new SampleJsonSchemaGeneratorSettings { SchemaType = SchemaType.OpenApi3 });

var schema = generator.Generate("{...}");

You can reconstruct a JsonSchema object from a JSON string using the asynchronous JsonSchema.FromJsonAsync() method.

schema = await JsonSchema.FromJsonAsync(schemaData);

The NJsonSchema.SampleJsonSchemaGenerator allows you to create a JSON Schema by providing a sample JSON object.

By default, it generates schemas following the standard JSON Schema specification. Use SampleJsonSchemaGeneratorSettings to configure the generator.

var generator = new SampleJsonSchemaGenerator(new SampleJsonSchemaGeneratorSettings());

var schema = generator.Generate("{...}");

To validate JSON data, use the Validate method on a JsonSchema instance. The method returns a collection of errors that you can iterate through to inspect the Path and Kind of each validation failure.

var schema = JsonSchema.FromType<Person>();
var errors = schema.Validate("{...}");

foreach (var error in errors)
    Console.WriteLine(error.Path + ": " + error.Kind);

Use the CSharpGenerator class from NJsonSchema.CodeGeneration to transform a JSON schema into C# classes. The GenerateFile() method returns a string containing the C# code for all classes defined in the schema.

var generator = new CSharpGenerator(schema);
var file = generator.GenerateFile();