Valit is dead simple validation for .NET Core. No more if-statements all around your code. Write nice and clean fluent validators instead!

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Valit is available on NuGet.

Install-Package Valit -Version 2.0.0

dotnet add package Valit --version 2.0.0

In order to create a validator you need to go through few steps. It's worth mentioning that not all of them are mandatory. The steps are:

• creating new instance of validator using Create() static method.
• choosing validation strategy using WithStrategy() method (not required).
• selecting property using Ensure() method and defining rules for it.
• Extending rules with custom errors (such as messages or error codes), tags and conditions. (not required).
• applying created rules to an object using For() method.

Having the validator created, simply invoke Validate() method which will produce the result with all the data.

Let's try it out with very practical example. Imagine that your task is to validate model sent from registration page of your app. The example object might look as follows:

    public class RegisterModel
    {
        public string Email { get; set; }        
        public string Password { get; set; }
        public ushort Age { get; set ;}
    }

These are the validation criteria:

• Email is required and needs to be a proper email address
• Password is required and needs to be at least 10 characters long
• Age must be greater than 16

This is how you can handle such scenario using Valit:

        void ValidateModel(RegisterModel model)
        {
            var result = ValitRules<RegisterModel>
                .Create()
                .Ensure(m => m.Email, _=>_
                    .Required()
                    .Email())
                .Ensure(m => m.Password, _=>_ 
                    .Required()
                    .MinLength(10))
                .Ensure(m => m.Age, _=>_
                    .IsGreaterThan(16))
                .For(model)
                .Validate();

            if(result.Succeeded)
            {
                // do something on success
            }
            else 
            {
                // do something on failure
            }
        }

Pretty cool, right? Of course, the above example was fairly simple but trust us. From now on, even complicated validation criterias won't scare you anymore ;)

If you're looking for documentation, you can find it here.

Want to help us develop Valit? Awesome! Here you can find contributor guide ;)