What are some examples of validation attributes in ASP.NET?

What are some examples of validation attributes in ASP.NET?

In ASP.NET, common validation attributes include Required, StringLength, Range, and RegularExpression. Would you like to see examples of each?

Yes, please provide examples for each of those validation attributes.

Sure!

1. Required: Ensures a field is not empty.

   [Required(ErrorMessage = "Name is required")] 
   public string Name { get; set; }
   

2. StringLength: Sets a maximum length for a string.

   [StringLength(100, ErrorMessage = "Name can't be longer than 100 characters")] 
   public string Name { get; set; }
   

3. Range: Validates that a number is within a specified range.

   [Range(1, 100, ErrorMessage = "Value must be between 1 and 100")] 
   public int Age { get; set; }
   

4. RegularExpression: Validates a string against a regex pattern.

   [RegularExpression("^[a-zA-Z]*$, ErrorMessage = "Only letters are allowed")] 
   public string AlphabeticField { get; set; }
   

Would you like more details on any specific attribute?

Can you explain how to use the RegularExpression attribute in more detail?

Certainly! The RegularExpression attribute allows you to specify a regex pattern that the input must match. For example:

[RegularExpression("^[a-zA-Z]+$, ErrorMessage = "Only letters are allowed")] 
public string AlphabeticField { get; set; }

In this case, the input must consist only of letters. If the input contains any other characters, the validation will fail, and the specified error message will be displayed.