How do you implement data validation and model binding in a .NET Core Web API?

Data validation and model binding are important aspects of a .NET Core Web API. Model binding refers to the process of mapping the data from HTTP requests to the model classes in the application. Data validation is the process of ensuring that the data received from the client is valid and meets certain criteria before it is used by the application. Here's how you can implement data validation and model binding in a .NET Core Web API:

1. Model binding: To implement model binding in a .NET Core Web API, you can use the [FromBody] and [FromQuery] attributes to specify the source of the data. For example, you can use the [FromBody] attribute to bind data from the request body to a model class, like this:

[HttpPost]
public IActionResult AddCustomer([FromBody] Customer customer)
{
    // Do something with the customer object
    return Ok();
}

 

2. Data validation: To implement data validation in a .NET Core Web API, you can use the [Required], [Range], and [RegularExpression] attributes to specify the validation rules for the model properties. For example, you can use the [Required] attribute to ensure that a property is not null, like this:

public class Customer
{
    [Required]
    public string Name { get; set; }
}

You can also use the ModelState.IsValid property to check if the data received from the client is valid, like this:

[HttpPost]
public IActionResult AddCustomer([FromBody] Customer customer)
{
    if (!ModelState.IsValid)
    {
        return BadRequest(ModelState);
    }

    // Do something with the customer object
    return Ok();
}


By following these best practices, you can ensure that your .NET Core Web API is able to handle data validation and model binding effectively.