iam-mholle/FluentBuilder

A project which uses Source Generation to create a FluentBuilder for a specified model or DTO

Projects

See also this blog: mstack.nl - source-generators.

CSharp.SourceGenerators.Extensions

See this page.

FluentBuilder

A project which uses Source Generation to create a FluentBuilder for a specified model or DTO.

This project is based on Tom Phan : "auto-generate-builders-using-source-generator-in-net-5".

Install

You can install from NuGet using the following command in the package manager window:

Install-Package FluentBuilder

Or via the Visual Studio NuGet package manager or if you use the dotnet command:

dotnet add package FluentBuilder

1️⃣ Usage on a existing class

Annotate a class

Annotate an existing class with [FluentBuilder.AutoGenerateBuilder] to indicate that a FluentBuilder should be generated for this class:

[AutoGenerateBuilder]
public class User
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public DateTime? Date { get; set; }
}

Use FluentBuilder

using System;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var user = new UserBuilder()
                .WithFirstName("Test")
                .WithLastName("User")
                .Build();

            Console.WriteLine($"{user.FirstName} {user.LastName}");
        }
    }
}

Use FluentBuilder when the class has a default constructor

[AutoGenerateBuilder]
public class User
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public DateTime? Date { get; set; }

    public User()
    {
        FirstName = "test";
    }
}

using System;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var user = new UserBuilder()
                .WithLastName("User")
                .Build(false); // ⭐ Provide `false` for `useObjectInitializer` here.

            Console.WriteLine($"{user.FirstName} {user.LastName}");
        }
    }
}

Using FluentBuilder when a class has an Array or IEnumerable<T> property

[AutoGenerateBuilder]
public class UserDto
{
    public IEnumerable<EmailDto> SecondaryEmails { get; set; }

    public int[] IntArray { get; set; }
}

var user = new UserDtoBuilder()
    .WithIntArray(ib => ib         // 👈 Use a Integer Array Builder
        .Add(1)                    // Add a normal integer

        .Add(() => 2)              // Add an integer with a Func<>
        .Build()
    )
    .WithSecondaryEmails(sb => sb  // 👈 Use a EmailDto IEnumerable Builder
        .Add(new EmailDto())       // Add a normal EmailDto using new() constructor

        .Add(() => new EmailDto()) // Add an EmailDto using Func<>

        .Add(eb => eb              // 👈 Use a EmailDto IEnumerable Builder to add an EmailDto
            .WithPrimary(true)
            .Build()
        )
        .Build()
    )
    .Build();

Using FluentBuilder when a class has an IDictionary<TKey, TValue> property

[AutoGenerateBuilder]
public class UserDto
{
    public IDictionary<string, int> Tags { get; set; }
}

var user = new UserDtoBuilder()
    .WithTags(db => db      // 👈 Use a Dictionary<TKey, TValue> Builder
        .Add("test", 123)   // Add a key with value

        .Add(() => new KeyValuePair<string, int>("x", 42)) // Add a KeyValuePair with a Func<>
        .Build()
    )
    .Build();

2️⃣ Define a class which needs to act as a builder

This scenario is very usefull when you cannot modify the class to annotate it.

Create a public and partial builder class

And annotate this class with [AutoGenerateBuilder(typeof(XXX))] where XXX is the type for which you want to generate a FluentBuilder.

[AutoGenerateBuilder(typeof(UserDto))]
public partial class MyUserDtoBuilder
{
}

Use FluentBuilder

using System;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var user = new MyUserDtoBuilder() // 👈 Just use your own Builder
                .WithFirstName("Test")
                .WithLastName("User")
                .Build();

            Console.WriteLine($"{user.FirstName} {user.LastName}");
        }
    }
}