DynamicForms.FormValidation 0.1.0

DynamicForms.FormValidation

Server-side form validation library for .NET compatible with @moe1399/ngx-dynamic-forms. Use the same form configuration and validation rules on both client and server.

Installation

dotnet add package DynamicForms.FormValidation

Usage

using DynamicForms.FormValidation;
using DynamicForms.FormValidation.Models;
using System.Text.RegularExpressions;

// Register custom validators (same logic as Angular/Node.js)
ValidatorRegistry.Instance.Register("australianPhoneNumber", (value, _, _, _) =>
{
    if (value == null) return true;
    var phone = value.ToString()?.Replace(" ", "") ?? "";
    return Regex.IsMatch(phone, @"^(\+61|0)[2-478]\d{8}$");
});

// Use the same form config as your Angular app
var formConfig = new FormConfig
{
    Id = "contact-form",
    Fields = new List<FormFieldConfig>
    {
        new FormFieldConfig
        {
            Name = "email",
            Label = "Email",
            Type = FieldType.Email,
            Validations = new List<ValidationRule>
            {
                new ValidationRule { Type = ValidationRuleType.Required, Message = "Email is required" },
                new ValidationRule { Type = ValidationRuleType.Email, Message = "Invalid email format" }
            }
        },
        new FormFieldConfig
        {
            Name = "phone",
            Label = "Phone",
            Type = FieldType.Text,
            Validations = new List<ValidationRule>
            {
                new ValidationRule
                {
                    Type = ValidationRuleType.Custom,
                    CustomValidatorName = "australianPhoneNumber",
                    Message = "Invalid Australian phone number"
                }
            }
        }
    }
};

// Validate submitted form data
var formData = new Dictionary<string, object?>
{
    { "email", "test@example.com" },
    { "phone", "0412345678" }
};

var result = FormValidator.ValidateForm(formConfig, formData);

if (!result.Valid)
{
    foreach (var error in result.Errors)
    {
        Console.WriteLine($"{error.Field}: {error.Message}");
    }
}

API

FormValidator.ValidateForm(config, data)

Validates form data against a form configuration.

Parameters:

• config: FormConfig - The form configuration (same structure as @moe1399/ngx-dynamic-forms)
• data: Dictionary<string, object?> - The form data to validate

Returns: ValidationResult

public class ValidationResult
{
    public bool Valid { get; set; }
    public List<FieldValidationError> Errors { get; set; }
}

public class FieldValidationError
{
    public string Field { get; set; }      // e.g., "email" or "contacts[0].phone"
    public string Message { get; set; }
    public string Rule { get; set; }       // Validation type that failed
}

FormValidator.ValidateFieldValue(fieldConfig, value, formData?)

Validates a single field value.

Parameters:

• fieldConfig: FormFieldConfig - The field configuration
• value: object? - The value to validate
• formData: Dictionary<string, object?>? - Optional full form data for contextual validation

Returns: ValidationResult

ValidatorRegistry.Instance

Singleton registry for custom validators.

// Register a single validator
ValidatorRegistry.Instance.Register("validatorName", (value, parameters, fieldConfig, formData) =>
{
    return true; // or false
});

// Register multiple validators
ValidatorRegistry.Instance.RegisterAll(new Dictionary<string, CustomValidatorFn>
{
    { "validator1", (v, _, _, _) => true },
    { "validator2", (v, _, _, _) => true }
});

// Check if validator exists
ValidatorRegistry.Instance.Has("validatorName");

// List all registered validators
ValidatorRegistry.Instance.List();

// Remove a validator
ValidatorRegistry.Instance.Unregister("validatorName");

// Clear all validators
ValidatorRegistry.Instance.Clear();

Built-in Validators

ASP.NET Core Example

using DynamicForms.FormValidation;
using DynamicForms.FormValidation.Models;
using System.Text.Json;

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

// Register validators at startup
ValidatorRegistry.Instance.Register("australianPhoneNumber", (value, _, _, _) =>
{
    if (value == null) return true;
    var phone = value.ToString()?.Replace(" ", "") ?? "";
    return Regex.IsMatch(phone, @"^(\+61|0)[2-478]\d{8}$");
});

// Form config (could be loaded from database)
var formConfig = new FormConfig { /* ... */ };

app.MapPost("/api/submit", async (HttpContext context) =>
{
    var body = await new StreamReader(context.Request.Body).ReadToEndAsync();
    var data = JsonSerializer.Deserialize<Dictionary<string, object?>>(body)
        ?? new Dictionary<string, object?>();

    var result = FormValidator.ValidateForm(formConfig, data);

    if (!result.Valid)
    {
        return Results.BadRequest(new { errors = result.Errors });
    }

    // Process valid form data
    return Results.Ok(new { success = true });
});

app.Run();

JSON Deserialization

The library works with System.Text.Json for deserializing form configurations:

var json = @"{
    ""id"": ""my-form"",
    ""fields"": [
        {
            ""name"": ""email"",
            ""label"": ""Email"",
            ""type"": ""email"",
            ""validations"": [
                { ""type"": ""required"", ""message"": ""Email is required"" }
            ]
        }
    ]
}";

var config = JsonSerializer.Deserialize<FormConfig>(json, new JsonSerializerOptions
{
    PropertyNameCaseInsensitive = true
});

var result = FormValidator.ValidateForm(config!, formData);

License

MIT