Entity Framework MaxLength Data Annotation

The MaxLength attribute allows you to specify additional property validations. It is applied to a property to specify a maximum number of characters or bytes for the column that the property should map to.

The following example specifies that the Title column in the Books table has a maximum length of 12 characters.

public class Book
{
    public int BookId { get; set; }
    [MaxLength(12)]
    public string Title { get; set; }
}

Try it

If you set a value of the Title property greater than the specified length in the MaxLength attribute, EF will throw an EntityValidationError.

Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.

Try it

MaxLength attribute can also be used with MinLength attribute.

public class Book
{
    public int BookId { get; set; }
    [MaxLength(12), MinLength(5)]
    public string Title { get; set; }
}

Try it