Check availability of usernames in database and validate

you can create a custom attribute for that https://www.sharpencode.com/article/MVC/data-annotations

public class UserNameCheck:ValidationAttribute
{
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
//here you could fetch data from database
string[] names = {"sachin","arjun","vikash","Govinda","Salman" };
Employee emp = (Employee)validationContext.ObjectInstance;
bool istrue = names.Any(x => x == emp.Name);
if (istrue)
{
return new ValidationResult("UserName is in use");
}
return ValidationResult.Success;
}
}
in model class
[UserNameCheck]
public string Name { get; set; }

2 Replies

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Sachin Singh5y ago
Accepted answer
you can create a custom attribute for that https://www.sharpencode.com/article/MVC/data-annotations
public class UserNameCheck:ValidationAttribute
     {
        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
           //here you could fetch data from database
            string[] names = {"sachin","arjun","vikash","Govinda","Salman" };
            Employee emp = (Employee)validationContext.ObjectInstance;
            bool istrue = names.Any(x => x == emp.Name);
            if (istrue)
            {
                return new ValidationResult("UserName is in use");
            }
            return ValidationResult.Success;
        }
     }

in model class
  [UserNameCheck]
         public string Name { get; set; }
Varun Setia5y ago
Use remote validation, it is loosely coupled, https://www.c-sharpcorner.com/blogs/remote-validation-in-mvc-5-using-remote-attribute