Data Annotations

Ref: http://www.asp.net/mvc/overview/older-versions/mvc-music-store/mvc-music-store-part-6

• Required – Indicates that the property is a required field
• DisplayName – Defines the text we want used on form fields and validation messages
• StringLength – Defines a maximum length for a string field
• Range – Gives a maximum and minimum value for a numeric field
• Bind – Lists fields to exclude or include when binding parameter or form values to model properties
• ScaffoldColumn – Allows hiding fields from editor forms

Code: https://github.com/jasonccliu/mvcdemo/commit/2180812eb8570357240cdf845984d08e61ffb3d4

呈現名稱
[Display(Name="First Name")]

必要欄位
[Required(ErrorMessage="Please provide First Name", AllowEmptyStrings = false)]

電子郵件
[EmailAddress]

Useful Resources

http://www.c-sharpcorner.com/article/data-annotations-and-validation-in-mvc/

http://www.c-sharpcorner.com/blogs/validation-in-asp-net-mvc-using-dataannotations

https://www.c-sharpcorner.com/article/dataannotations-in-depth/

-- 用客製屬性方式來檢查使用者輸入的資料及格式

-- MetaData
[ApplicationOwnerContactAttribute(false, ErrorMessage = "The {0} isn't valid")]
public string AppOwnerContact;

 public class ApplicationOwnerContactAttribute : ValidationAttribute
    {

        private bool ThrowExcepcion;

        public ApplicationOwnerContactAttribute(Boolean isThrowException)
        {
            ThrowExcepcion = isThrowException;
        }


        public override bool IsValid(object value)
        {
            try
            {
                Worker wrkr = new Worker(value.ToString());

                if (wrkr == null || wrkr.FullName == null)
                {
                    if (ThrowExcepcion)
                        throw new ArgumentException(
                            "The user account is incorrect!");
                    else
                        return false;
                }
            }
            catch (Exception)
            {
                return false;
            }

            return true;
        }
    }