Utility Functions

ForEach

Adds a validator to validate all items in a collection from the target of the selector expression.

Method

Example Usage

var validator = new ValidatorBuilder<Employee>()
    .ForEach(
        e => e.Skills,
        builder => 
        {
            builder.NotNull().MinLength(3);
        })
    .Build();
    
// this will produce two broken rules
var result = validator.Validate(new Employee 
    { 
        Skills = new[] { "Dev", "No", "Junk", null }
    });

foreach (var rule in result.BrokenRules)
{
    Console.WriteLine($"[{rule.Rule}] {rule.Key} {rule.Message}")
}

// output
// [MinLength] e.Skills[1] Value must have minimum length of 3
// [NotNull] e.Skills[3] Value cannot be null

Message

Aggregates broken rules into a single broken rule with the specified message. This function should be added last and only once to the builder to avoid strange results.

Method

Example Usage

Using message string

var validator = new ValidatorBuilder<string>()
    .StartsWith("d")
    .EndsWith("m")
    .Email()
    .Message("This is not a drum")
    .Build();
    
// this will produce two broken rules (StartsWith,Email)
var result = validator.Validate("everything is a drum");

foreach (var rule in result.BrokenRules)
{
    Console.WriteLine($"[{rule.Rule}]: {rule.Message}")
}

// output
// [StartsWith,Email]: This is not a drum

Using function returning string

var validator = new ValidatorBuilder<string>()
    .StartsWith("d")
    .EndsWith("m")
    .Email()
    // access the context to build the message
    .Message(ctx => $"This is not a drum ({ctx.BrokenRules.Count})")
    .Build();
    
// this will produce two broken rules (StartsWith,Email)
var result = validator.Validate("everything is a drum");

foreach (var rule in result.BrokenRules)
{
    Console.WriteLine($"[{rule.Rule}]: {rule.Message}")
}

// output
// [StartsWith,Email]: This is not a drum (2)