Phema.Validation 3.1.10

.NET Standard 2.0
Install-Package Phema.Validation -Version 3.1.10
dotnet add package Phema.Validation --version 3.1.10
<PackageReference Include="Phema.Validation" Version="3.1.10" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add Phema.Validation --version 3.1.10
The NuGet Team does not provide support for this client. Please contact its maintainers for support.
#r "nuget: Phema.Validation, 3.1.10"
#r directive can be used in F# Interactive, C# scripting and .NET Interactive. Copy this into the interactive tool or source code of the script to reference the package.
// Install Phema.Validation as a Cake Addin
#addin nuget:?package=Phema.Validation&version=3.1.10

// Install Phema.Validation as a Cake Tool
#tool nuget:?package=Phema.Validation&version=3.1.10
The NuGet Team does not provide support for this client. Please contact its maintainers for support.


Build Status Nuget Nuget

A simple, lightweight, fluent and extensible validation library for .NET Core


$> dotnet add package Phema.Validation

Core concepts

  • IValidationContext - Scoped service to store all validation details
  • IValidationCondition - Contains a validation checks (e.g. Is(() => ...))
  • IValidationDetail - When IValidationCondition is not valid adds to IValidationContext.ValidationDetails
  • ValidationSeverity - Validation error level, used in IValidationContext.ValidationSeverity and IValidationDetail.ValidationSeverity
  • IValidationScope - Is a nested validation context with validation path and severity override

Usage (ASP.NET Core, HostedService examples)

// Add `IValidationContext` as scoped service
services.AddValidation(options => ...);

// Get or inject
var validationContext = serviceProvider.GetRequiredService<IValidationContext>();

// Validation key will be `Name` using default validation part provider
validationContext.When(person, p => p.Name)
  .Is(name => name == null)
  .AddValidationDetail("Name must be set");

// Validation key will be `Address.Locations[0].Latitude` using default validation part provider
validationContext.When(person, p => p.Address.Locations[0].Latitude)
  .Is(latitude => ...custom check...)
  .AddValidationDetail("Some custom check failed");

Validation conditions

  • Monads are not composable, so Is and IsNot, IsNull and IsNotNull... duplication
// Check for Phema.Validation.Conditions namespace
validationContext.When(person, p => p.Name)
  .AddValidationDetail("Name must be set");

// Use multiple conditions (joined with AND)
validationContext.When(person, p => p.Name)
  // AND
  // .IsNull()
  // .IsEqual()
  // .IsNotUrl()
  // .IsNotEmail()
  // .IsMatch(regex)
  .AddValidationDetail("Name should be less than 20");

// DateTime conditions
validationContext.When(task, t => t.DueDate)
  .AddValidationDetail("Due date must be in Utc");

// Type checks
validationContext.When(person, p => p.Car)
  .IsType<Ferrari>(typed => typed.Is(ferarriCar => ...Some Ferrari specific checks...))
  .AddValidationDetail("You have Ferrari car, but ...");

Validation details

var validationDetails = validationContext
  .When(person, p => p.Age)
  // Validation check is failed, validation condition is valid
  .Is(() => false)
  .AddValidationDetail("Age must be set");

// Use deconstruction
var (key, message) = validationContext
  .When(person, p => p.Age)
  .AddValidationDetail("Age must be set");

// More deconstruction
var (key, message, isValid) = validationContext
  .When(person, p => p.Age)
  .AddValidationDetail("Age must be set");

// Even more deconstruction!
var (key, message, isValid, severity) = validationContext
  .When(person, p => p.Age)
  .AddValidationDetail("Age must be set");

Check validation

// Throw exception when details severity greater than ValidationContext.ValidationSeverity
validationContext.When(person, p => p.Address)
  .AddValidationFatal("Address is not presented!!!"); // If invalid throw ValidationConditionException

// Check if context is valid
validationContext.EnsureIsValid(); // If invalid throw ValidationContextException

// Check concrete validation details
validationContext.IsValid(person, p => p.Age);
validationContext.IsNotValid(person, p => p.Age);
validationContext.EnsureIsValid(person, p => p.Age);

Compose and reuse validation rules with extensions

  • Call is allocation free
  • Static checks
// Extensions
public static void ValidateCustomer(this IValidationContext validationContext, Customer customer)
  // Some checks

  • Write your own middleware or validation components/validators on top of IValidationContext

Validation part resolvers

  • ValidationPartResolver is a delegate, trying to get string valdiation part from MemberInfo
  • Use built in resolvers with ValidationPartResolvers static class: Default, DataMember, PascalCase, CamelCase
// Configure DataMember validation part resolver
services.AddValidation(options =>

// Override validation parts with `DataMemberAttribute`
[DataMember(Name = "name")]
public string Name { get; set; }

Validation scopes

  • Use scopes when you need to have:
    • Same nested validation path multiple times
    • Empty validation details collection (syncing with parent context/scope)
    • ValidationSeverity override
// Validation key will be `Child.*ValidationPart*`
ValidateChild(validationContext.CreateScope(parent, p => p.Child))

// Validation key will be `Address.Locations[0].*ValidationPart*`
ValidateLocation(validationContext.CreateScope(person, p => p.Address.Locations[0]))

// Override local scope ValidationSeverity
using (var scope = validationContext.CreateScope(person, p => p.Address, ValidationSeverity.Warning))
  // Some scope validation checks syncing with validationContext

High performance with non-expression constructions

validationContext.When("key", value)
  .AddValidationDetail("Value is null");

validationContext.CreateScope("key", ValidationSeverity.Warning);

Product Versions
.NET net5.0 net5.0-windows net6.0 net6.0-android net6.0-ios net6.0-maccatalyst net6.0-macos net6.0-tvos net6.0-windows
.NET Core netcoreapp2.0 netcoreapp2.1 netcoreapp2.2 netcoreapp3.0 netcoreapp3.1
.NET Standard netstandard2.0 netstandard2.1
.NET Framework net461 net462 net463 net47 net471 net472 net48
MonoAndroid monoandroid
MonoMac monomac
MonoTouch monotouch
Tizen tizen40 tizen60
Xamarin.iOS xamarinios
Xamarin.Mac xamarinmac
Xamarin.TVOS xamarintvos
Xamarin.WatchOS xamarinwatchos
Compatible target framework(s)
Additional computed target framework(s)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last updated
3.1.10 369 10/12/2019
3.1.9 413 9/27/2019
3.1.8 359 9/25/2019
3.1.7 277 9/15/2019
3.1.6 241 9/8/2019
3.1.5 220 9/7/2019
3.1.4 220 9/7/2019
3.1.3 241 9/7/2019
3.1.2 222 8/25/2019
3.1.1 216 8/24/2019
3.1.0 218 8/23/2019
3.0.9 216 8/23/2019
3.0.8 224 8/22/2019
3.0.7 221 8/16/2019
3.0.6 245 7/30/2019
3.0.5 220 7/29/2019
3.0.4 241 7/29/2019
3.0.3 228 7/28/2019
3.0.2 219 7/21/2019