JSON to C# POCO Converter

A simple tool for converting JSON data into C# POCO (Plain Old CLR Object) classes with support for records, customizable property access, nullable types, and various collection types.

Features

• Convert JSON to C# classes or records
• Support for nested objects and arrays
• Customizable property access patterns
• Optional JSON property name attributes
• Nullable type support
• Required property markers
• Default value initialization
• Multiple array type options
• Primary constructor support for records

Settings

Basic Settings

• Namespace: Set the namespace for generated classes (default: "JsonToCsharp")
• RootTypeName: Set the name for the root class/record (default: "Root")
• UseRecords: Generate C# records instead of classes
• UsePrimaryConstructor: Use primary constructor syntax for records (C# 9.0+)

Property Settings

• PropertyAccess: Control property accessor patterns

  • Mutable: Generate { get; set; } properties
  • Immutable: Generate { get; init; } properties (C# 9.0+)

• ArrayType: Choose collection type for arrays

  • IReadOnlyList<T>: Immutable list interface
  • List<T>: Standard mutable list
  • T[]: Array type

• AddAttribute: Add [JsonPropertyName] attributes for JSON serialization

• IsNullable: Generate nullable reference types

• IsRequired: Add required keyword to properties (C# 11.0+)

• IsDefaultInitialized: Initialize properties with default values

Examples

Basic Class Generation

Input JSON:

{
    "name": "John",
    "age": 30,
    "isEmployee": true
}

Settings:

var options = new ConversionSettings
{
    Namespace = "MyNamespace",
    UseRecords = false,
    PropertyAccess = PropertyAccess.Mutable
};

Output:

namespace MyNamespace;

public class Root
{
    [JsonPropertyName("name")]
    public string Name { get; set; }
    
    [JsonPropertyName("age")]
    public int Age { get; set; }
    
    [JsonPropertyName("isEmployee")]
    public bool IsEmployee { get; set; }
}

Record with Primary Constructor

Settings:

var options = new ConversionSettings
{
    UseRecords = true,
    UsePrimaryConstructor = true,
    AddAttribute = true
};

Output:

public record Root(
    [property: JsonPropertyName("name")] string Name,
    [property: JsonPropertyName("age")] int Age,
    [property: JsonPropertyName("isEmployee")] bool IsEmployee
);

Nullable and Required Properties

Settings:

var options = new ConversionSettings
{
    IsNullable = true,
    IsRequired = true,
    PropertyAccess = PropertyAccess.Immutable
};

Output:

public class Root
{
    [JsonPropertyName("name")]
    public required string? Name { get; init; }
    
    [JsonPropertyName("age")]
    public required int? Age { get; init; }
}

Array Type Options

Input JSON:

{
    "items": ["A", "B", "C"]
}

Settings for different array types:

// IReadOnlyList
options.ArrayType = ArrayType.IReadOnlyList;
// Output: public IReadOnlyList<string> Items { get; init; }

// List
options.ArrayType = ArrayType.List;
// Output: public List<string> Items { get; init; }

// Array
options.ArrayType = ArrayType.Array;
// Output: public string[] Items { get; init; }

Default Initialization

Settings:

var options = new ConversionSettings
{
    IsDefaultInitialized = true,
    PropertyAccess = PropertyAccess.Immutable
};

Output:

public class Root
{
    public string Name { get; init; } = string.Empty;
    public IReadOnlyList<string> Tags { get; init; } = [];
    public Address Address { get; init; } = new();
}

Type Mapping

The converter automatically maps JSON types to C# types:

• JSON strings → string
• JSON numbers → int or double
• JSON booleans → bool
• JSON arrays → IReadOnlyList<T>, List<T>, or T[]
• JSON objects → Nested classes/records
• JSON dates → DateTime