Contents tagged with ASP.NET WebAPI

  • Consolidate Model Validation Errors as a Single String in ASP.NET Web API

    As we all know that we can do validation in ASP.NET MVC by decorating the model with validation attributes and when the page is generated by the framework it will automatically generate the client side validation scripts. You can read more about it in the Microsoft Documentation here. Normally the output will be like in the figure given below.

    Let's see how we can use the same mechanism in ASP.NET WebAPI to do the validation. I have created a model class as shown below

    public class Employee
        {
            [Required]
            [MaxLength(50, ErrorMessage="First name should not exceed 50 characters")]
            public string FirstName { get; set; }
            [Required]
            [MaxLength(50, ErrorMessage="Last name should not exceed 50 characters")]
            public string LastName { get; set; }
            [Required]
            [MaxLength(200, ErrorMessage="Address should not exceed 200 characters")]
            public string Address { get; set; }
            [Required]
            [EmailAddress(ErrorMessage="Email is invalid")]
            [MaxLength(50, ErrorMessage="EmailAddress should not exceed 50 characters")]
            public string EmailAddress { get; set; }
        }
    

    And created a POST method as given below which basically validates the model and if any errors are found then returns an error as response.

    public HttpResponseMessage Post([FromBody] Employee emp)
            {
                if (!ModelState.IsValid)
                    return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, ModelState);
                return Request.CreateResponse(HttpStatusCode.Created, emp);
            }
    

    Categories: C#, Web Developement, MVC, Web API