System.Collections.Immutable 9.0.0

About

This package provides collections that are thread safe and guaranteed to never change their contents, also known as immutable collections. Like strings, any methods that perform modifications will not change the existing instance but instead return a new instance. For efficiency reasons, the implementation uses a sharing mechanism to ensure that newly created instances share as much data as possible with the previous instance while ensuring that operations have a predictable time complexity.

The System.Collections.Immutable library is built-in as part of the shared framework in .NET Runtime. The package can be installed when you need to use it in other target frameworks.

How to Use

using System.Collections.Immutable;

// Create immutable set of strings
ImmutableHashSet<string> colors = ImmutableHashSet.Create("Red", "Green", "Blue");

// Create a new set by adding and removing items from the original set
ImmutableHashSet<string> colorsModified = colors.Remove("Red").Add("Orange");

foreach (string s in colorsModified)
{
    Console.WriteLine(s);
}

/* Example output:
 Blue
 Green
 Orange
 */

Main Types

The main types provided by this library are:

  • System.Collections.Immutable.ImmutableArray
  • System.Collections.Immutable.ImmutableArray<T>
  • System.Collections.Immutable.ImmutableDictionary
  • System.Collections.Immutable.ImmutableDictionary<TKey,TValue>
  • System.Collections.Immutable.ImmutableHashSet
  • System.Collections.Immutable.ImmutableHashSet<T>
  • System.Collections.Immutable.ImmutableList
  • System.Collections.Immutable.ImmutableList<T>
  • System.Collections.Immutable.ImmutableQueue
  • System.Collections.Immutable.ImmutableQueue<T>
  • System.Collections.Immutable.ImmutableSortedDictionary
  • System.Collections.Immutable.ImmutableSortedDictionary<TKey,TValue>
  • System.Collections.Immutable.ImmutableSortedSet
  • System.Collections.Immutable.ImmutableSortedSet<T>
  • System.Collections.Immutable.ImmutableStack
  • System.Collections.Immutable.ImmutableStack<T>
  • System.Collections.Frozen.FrozenDictionary
  • System.Collections.Frozen.FrozenDictionary<TKey, TValue>
  • System.Collections.Frozen.FrozenSet
  • System.Collections.Frozen.FrozenSet<T>

Additional Documentation

Feedback & Contributing

System.Collections.Immutable is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.

Showing the top 20 packages that depend on System.Collections.Immutable.

Packages Downloads
HotChocolate.Abstractions
Contains common abstractions used between the Hot Chocolate GraphQL type system and the GraphQL query execution engine.
4,378
HotChocolate.Abstractions
Contains common abstractions used between the Hot Chocolate GraphQL type system and the GraphQL query execution engine.
3,923
Microsoft.CodeAnalysis.Common
A shared package used by the Microsoft .NET Compiler Platform ("Roslyn"). Do not install this package manually, it will be added as a prerequisite by other packages that require it. More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/260d16a8ee0ab42d94d8dfdfe85a1279c85dcffd.
1,419
Microsoft.Diagnostics.Runtime
ClrMD is a set of advanced APIs for programmatically inspecting a crash dump of a .NET program much in the same way that the SOS Debugging Extensions (SOS) do. This allows you to write automated crash analysis for your applications as well as automate many common debugger tasks. In addition to reading crash dumps ClrMD also allows supports attaching to live processes.
1,417
System.Reflection.Metadata
This packages provides a low-level .NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. Commonly Used Types: System.Reflection.Metadata.MetadataReader System.Reflection.PortableExecutable.PEReader System.Reflection.Metadata.Ecma335.MetadataBuilder System.Reflection.PortableExecutable.PEBuilder System.Reflection.PortableExecutable.ManagedPEBuilder When using NuGet 3.x this package requires at least version 3.4.
1,416
System.Reflection.Metadata
This packages provides a low-level .NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. Commonly Used Types: System.Reflection.Metadata.MetadataReader System.Reflection.PortableExecutable.PEReader System.Reflection.Metadata.Ecma335.MetadataBuilder System.Reflection.PortableExecutable.PEBuilder System.Reflection.PortableExecutable.ManagedPEBuilder 30ab651fcb4354552bd4891619a0bdd81e0ebdbf When using NuGet 3.x this package requires at least version 3.4.
1,413
HotChocolate.Abstractions
Contains common abstractions used between the Hot Chocolate GraphQL type system and the GraphQL query execution engine.
499
Microsoft.CodeAnalysis.Common
A shared package used by the Microsoft .NET Compiler Platform ("Roslyn"). Do not install this package manually, it will be added as a prerequisite by other packages that require it. More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/6a5a63bbc9f4449d9bd1e95a8f9624939c3ccdc3.
374
System.Reflection.Metadata
This packages provides a low-level .NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. Commonly Used Types: System.Reflection.Metadata.MetadataReader System.Reflection.PortableExecutable.PEReader System.Reflection.Metadata.Ecma335.MetadataBuilder System.Reflection.PortableExecutable.PEBuilder System.Reflection.PortableExecutable.ManagedPEBuilder
356
Microsoft.EntityFrameworkCore
Entity Framework Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations. EF Core works with SQL Server, Azure SQL Database, SQLite, Azure Cosmos DB, MySQL, PostgreSQL, and other databases through a provider plugin API. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
209
Microsoft.EntityFrameworkCore
Entity Framework Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations. EF Core works with SQL Server, Azure SQL Database, SQLite, Azure Cosmos DB, MySQL, PostgreSQL, and other databases through a provider plugin API. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
173
Microsoft.EntityFrameworkCore
Entity Framework Core is a lightweight and extensible version of the popular Entity Framework data access technology. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
115
SocketIoClientDotNet
This is the Socket.IO Client Library for .NET.
76
Microsoft.EntityFrameworkCore
Entity Framework Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations. EF Core works with SQL Server, Azure SQL Database, SQLite, Azure Cosmos DB, MySQL, PostgreSQL, and other databases through a provider plugin API. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
70
Microsoft.EntityFrameworkCore
Entity Framework Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations. EF Core works with SQL Server, Azure SQL Database, SQLite, Azure Cosmos DB, MySQL, PostgreSQL, and other databases through a provider plugin API. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
67
Microsoft.EntityFrameworkCore
Entity Framework Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations. EF Core works with SQL Server, Azure SQL Database, SQLite, Azure Cosmos DB, MySQL, PostgreSQL, and other databases through a provider plugin API. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
64
Microsoft.EntityFrameworkCore
Entity Framework Core is a lightweight and extensible version of the popular Entity Framework data access technology. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
62
EngineIoClientDotNet
This is the Engine.IO Client Library for C#.
61
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
61
Microsoft.EntityFrameworkCore
Entity Framework Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations. EF Core works with SQL Server, Azure SQL Database, SQLite, Azure Cosmos DB, MySQL, PostgreSQL, and other databases through a provider plugin API. Commonly Used Types: Microsoft.EntityFrameworkCore.DbContext Microsoft.EntityFrameworkCore.DbSet
60

https://go.microsoft.com/fwlink/?LinkID=799421

.NET Framework 4.6.2

.NET 8.0

  • No dependencies.

.NET 9.0

  • No dependencies.

.NET Standard 2.0

Version Downloads Last updated
10.0.0-preview.3.25171.5 7 04/12/2025
10.0.0-preview.2.25163.2 7 03/25/2025
10.0.0-preview.1.25080.5 10 02/25/2025
9.0.4 3 04/13/2025
9.0.3 7 03/11/2025
9.0.2 12 02/16/2025
9.0.1 13 01/19/2025
9.0.0 20 11/13/2024
9.0.0-rc.2.24473.5 15 10/16/2024
9.0.0-rc.1.24431.7 19 09/12/2024
9.0.0-preview.7.24405.7 17 08/14/2024
9.0.0-preview.6.24327.7 30 07/12/2024
9.0.0-preview.5.24306.7 23 06/13/2024
9.0.0-preview.4.24266.19 21 06/07/2024
9.0.0-preview.3.24172.9 25 04/12/2024
9.0.0-preview.2.24128.5 27 03/19/2024
9.0.0-preview.1.24080.9 34 02/18/2024
8.0.0 3,944 11/15/2023
8.0.0-rc.2.23479.6 30 10/22/2023
8.0.0-rc.1.23419.4 33 09/24/2023
8.0.0-preview.7.23375.6 45 08/29/2023
8.0.0-preview.6.23329.7 44 07/21/2023
8.0.0-preview.5.23280.8 41 06/20/2023
8.0.0-preview.4.23259.5 34 06/10/2023
8.0.0-preview.3.23174.8 29 07/14/2023
8.0.0-preview.2.23128.3 32 07/10/2023
8.0.0-preview.1.23110.8 41 06/25/2023
7.0.0 38 11/30/2022
7.0.0-rc.2.22472.3 45 12/19/2022
7.0.0-rc.1.22426.10 42 12/19/2022
7.0.0-preview.7.22375.6 33 09/15/2022
7.0.0-preview.6.22324.4 40 07/14/2023
7.0.0-preview.5.22301.12 39 07/11/2023
7.0.0-preview.4.22229.4 31 07/07/2023
7.0.0-preview.3.22175.4 34 06/10/2023
7.0.0-preview.2.22152.2 33 06/03/2022
7.0.0-preview.1.22076.8 40 12/19/2022
6.0.2-mauipre.1.22102.15 42 12/19/2022
6.0.2-mauipre.1.22054.8 38 07/11/2023
6.0.1 13 11/13/2024
6.0.0 369 11/09/2021
6.0.0-rc.2.21480.5 36 07/16/2023
6.0.0-rc.1.21451.13 29 06/26/2023
6.0.0-preview.7.21377.19 49 06/26/2023
6.0.0-preview.6.21352.12 41 10/12/2022
6.0.0-preview.5.21301.5 40 07/11/2023
6.0.0-preview.4.21253.7 54 10/13/2022
6.0.0-preview.3.21201.4 29 01/14/2023
6.0.0-preview.2.21154.6 28 07/09/2023
6.0.0-preview.1.21102.12 40 06/16/2022
5.0.0 1,548 01/26/2021
5.0.0-rc.2.20475.5 39 02/02/2023
5.0.0-rc.1.20451.14 35 04/08/2023
5.0.0-preview.8.20407.11 35 06/28/2023
5.0.0-preview.7.20364.11 37 07/09/2023
5.0.0-preview.6.20305.6 44 07/11/2023
5.0.0-preview.5.20278.1 35 06/28/2023
5.0.0-preview.4.20251.6 37 07/14/2023
5.0.0-preview.3.20214.6 50 05/25/2023
5.0.0-preview.2.20160.6 34 06/28/2023
5.0.0-preview.1.20120.5 46 10/17/2022
1.7.1 53 11/09/2020
1.7.0 4,536 01/26/2021
1.7.0-preview3.19551.4 37 06/07/2022
1.7.0-preview2.19523.17 29 06/27/2023
1.7.0-preview1.19504.10 28 07/11/2023
1.6.0 46 06/03/2022
1.6.0-rc1.19456.4 33 07/11/2023
1.6.0-preview9.19421.4 49 06/26/2023
1.6.0-preview9.19416.11 41 07/03/2023
1.6.0-preview8.19405.3 39 07/10/2023
1.6.0-preview7.19362.9 38 06/27/2023
1.6.0-preview6.19303.8 43 07/05/2023
1.6.0-preview6.19264.9 31 06/26/2023
1.6.0-preview5.19224.8 37 06/26/2023
1.6.0-preview4.19212.13 45 07/27/2022
1.6.0-preview3.19128.7 42 06/25/2022
1.6.0-preview.19073.11 35 06/05/2022
1.6.0-preview.18571.3 44 08/03/2022
1.5.0 37 08/05/2022
1.5.0-rc1 41 12/19/2022
1.5.0-preview2-26406-04 27 06/01/2022
1.5.0-preview1-26216-02 35 07/13/2023
1.4.0 165 11/01/2020
1.4.0-preview2-25405-01 36 09/26/2022
1.4.0-preview1-25305-02 31 12/03/2022
1.3.1 32 08/28/2022
1.3.0 38 11/25/2022
1.3.0-preview1-24530-04 45 07/08/2023
1.2.0 34 02/17/2023
1.2.0-rc2-24027 31 07/04/2023
1.1.38-beta-23516 42 07/13/2023
1.1.38-beta-23409 29 07/04/2023
1.1.38-beta-23225 32 07/11/2023
1.1.37 36 06/26/2023
1.1.37-beta-23109 27 06/27/2023
1.1.37-beta-23019 35 06/26/2023
1.1.36 29 06/27/2022
1.1.34-rc 49 06/27/2023
1.1.33-beta 31 06/16/2023
1.1.32-beta 31 06/27/2023