Using the Data Validation package
The Data Validation package is designed to provide out-of-the-box data validation to applications built with C#.
Validating an object using the ValidatorCollection
Data validation can be implemented in so many different ways. MADE provides the capability to perform data validation through its own IValidator interface that can be used to create consistent data validators.
Using the MADE.Data.Validation.ValidatorCollection based on a List type, you can construct a collection of IValidator instances which can be used to validate values.
For example, you might want a collection of validators that ensure that a value is provided, it has a minimum length, and it contains only alphanumeric characters.
Instead of implementing your own custom validation in your application, you can take advantage of the built-in IValidator implementation of this package and utilize them with the ValidatorCollection.
This can be achieved like the example below.
namespace App.Validations
{
using MADE.Data.Converters;
public class ApplicationConverters
{
private readonly ValidatorCollection RequiredAlphaNumericValidators = new ValidatorCollection
{
new RequiredValidator { Key = "Required" },
new AlphaNumericValidator { Key = "AlphaNumericOnly" },
};
public void EnsureValid(string value)
{
RequiredAlphaNumericValidators.Validate(value);
if (RequiredAlphaNumericValidators.IsInvalid)
{
throw new InvalidOperationException(string.Join(", ", RequiredAlphaNumericValidators.FeedbackMessages)));
}
}
}
}
The ValidatorCollection will loop through all of the IValidator instances that have been registered with it and validate the value with each one.
When there are errors, this will result in the FeedbackMessages collection being populated with validation messages which can be used to display to the user.
You also have the IsInvalid property which exposes where there are any validators that are invalid.
There is also control through a Validated event handler which you can use to trigger actions based on whether the validations have run in the collection.
Available IValidator types
IValidator types can be used on their own, as well as with the ValidatorCollection.
Here is a list of the in-box IValidators that you can use in your applications.
AlphaValidator
The AlphaValidator checks a string value contains only letter characters, i.e. a-z, ignoring casing.
If the value contains only letters, the validator will report valid; otherwise, it will report invalid.
AlphaNumericValidator
Similar to the AlphaValidator, the AlphaNumericValidator extends the characters in the validation to include numbers also.
Base64Validator
The Base64Validator checks whether a string value is a valid Base64 encoded string.
BetweenValidator
The BetweenValidator validates an IComparable value is between a configurable minimum and maximum range.
The range can be configured by setting the Min and Max values, as well as an Inclusive flag to configure whether the minimum and maximum values are included in the range (defaults to true).
The in-box System types which implement the IComparable interface can be found in the Microsoft documentation.
EmailValidator
The EmailValidator extends the in-box RegexValidator type to provide validating a string is a valid e-mail address.
The current pattern used to validate e-mail addresses is:
this.Pattern = @"^(?!\.)(""([^""\r\\]|\\[""\r\\])*""|" + @"([-a-zA-Z0-9!#$%&'*+/=?^_`{|}~]|(?<!\.)\.)*)(?<!\.)" + @"@[a-z0-9][\w\.-]*[a-z0-9]\.[a-z][a-z\.]*[a-z]$";
MADE.NET has a comprehensive set of test cases which validate the implementation with a variety of different valid and invalid email addresses.
GuidValidator
The GuidValidator checks whether a string value is a valid GUID.
The underlying implementation uses the Guid.TryParse method to validate the string.
IpAddressValidator
The IpAddressValidator is a simple data validator which ensures that a value is a valid IP address.
The implementation splits the IP address into each nibble and validates them based on the following criteria:
- Is less than 4 characters
- Is greater than 0 characters
- Is a digit
- Is a numeric value between 0 and 255
LatitudeValidator
The LatitudeValidator validates a value is within the valid range for a latitude value (-90 and 90).
LongitudeValidator
The LongitudeValidator validates a value is within the valid range for a longitude value (-180 and 180).
MacAddressValidator
The MacAddressValidator is a simple data validator which ensures that a value is a valid MAC address.
The implementation uses the .NET PhysicalAddress class to parse the provided value.
For more information on the PhysicalAddress class, see the Microsoft documentation.
MaxValueValidator
The MaxValueValidator validates an IComparable value is less than a configurable maximum value.
The maximum can be configured by setting the Max value.
The in-box System types which implement the IComparable interface can be found in the Microsoft documentation.
MinValueValidator
The MinValueValidator validates an IComparable value is greater than a configurable minimum value.
The minimum can be configured by setting the Min value.
The in-box System types which implement the IComparable interface can be found in the Microsoft documentation.
PredicateValidator
The PredicateValidator validates a value using a custom predicate to ensure that a condition is met.
RegexValidator
The RegexValidator is a generic data validator which validates a value based on a configurable regular expression pattern.
The pattern can be configured by setting the Pattern value.
RequiredValidator
The RequiredValidator is a data validator that ensures that the value provided exists.
This is determined based on the following criteria:
- The value is not null
- The value is a collection and contains items
- The value is a boolean and is true
- The value is a string and is not null or whitespace
Creating your own custom data validators
There are likely to be more advanced, custom scenarios for your own applications that need to extend the capabilities past the in-box IValidator types.
If you want to take advantage of what goes into a data validator, you can build your own using the MADE.Data.Validation.IValidator interface.
You can then build out your own, similar to our validators such as the RequiredValidator.
namespace MADE.Data.Validation.Validators
{
using System.Collections;
using MADE.Data.Validation.Extensions;
using MADE.Data.Validation.Strings;
public class RequiredValidator : IValidator
{
private string feedbackMessage = Resources.ResourceManager.GetString("RequiredValidator_FeedbackMessage");
public string Key { get; set; } = nameof(RequiredValidator);
public bool IsInvalid { get; set; }
public bool IsDirty { get; set; }
public string FeedbackMessage
{
get => this.feedbackMessage.IsNullOrWhiteSpace() ? Resources.RequiredValidator_FeedbackMessage : this.feedbackMessage;
set => this.feedbackMessage = value;
}
public void Validate(object value)
{
this.IsInvalid = DetermineIsInvalid(value);
this.IsDirty = true;
}
private static bool DetermineIsInvalid(object value)
{
switch (value)
{
case null:
return true;
case ICollection collection:
return collection.Count <= 0;
case bool isTrue:
return !isTrue;
case string str:
return str.IsNullOrWhiteSpace();
default:
return false;
}
}
}
}
If there is a common data validator you think is missing from MADE.NET, raise a tracking item on GitHub and we'll get it implemented.
Using FluentValidation with MADE.NET
The MADE.Data.Validation.FluentValidation package provides an easy way to take advantage of validation with the FluentValidation library validator framework.
Validating an object using the FluentValidatorCollection
Using the MADE.Data.Validation.FluentValidatorCollection<T> based on a List type, you can construct a collection of AbstractValidator instances which can be used to validate values.
This way, you can bring FluentValidation's out-of-the-box validators or your own custom validators based on the AbstractValidator type and get all the benefits of using the existing MADE.NET validation framework. This is great for example with input validator controls that currently support the MADE.NET validation framework!