Useful attributes in MVC

• StringLength Attribute :

Used to enforce minimum and maximum length of characters that are allowed in a data field. Let's understand this with an example. 

Namespace: 

System.ComponentModel.DataAnnotations

    [MetadataType(typeof(EmployeeMetaData))]
    public partial class Employee
    {
 
    }
 
    public class EmployeeMetaData
    {
        [StringLength (10,MinimumLength =5)]
        public string Name { get; set; }

    }

Range Attribute


Range attribute is used to validate DateTime fields, numeric fields.




    [MetadataType(typeof(EmployeeMetaData))]
    public partial class Employee
    {
 
    }
 
    public class EmployeeMetaData
    {
        [StringLength (10,MinimumLength =5)]
        public string Name { get; set; }
 
        [Range(1,100)]
        public string Age { get; set; }

        [Range(typeof(DateTime),"01/01/2010","01/01/2018")]
        public DateTime? DateofJoin { get; set; }
    }


Regular Expression Attribute


Regular expression attribute is used for pattern matching validation.




   [MetadataType(typeof(EmployeeMetaData))]
   public partial class Employee
   {
 
   }
 
   public class EmployeeMetaData
   {
       [RegularExpression(@"^(([A-za-z]+[\s]{1}[A-za-z]+)|([A-Za-z]+))$")]
       [StringLength (10,MinimumLength =5)]
       public string Name { get; set; }
   }

Or

        [RegularExpression(@"^(([A-za-z]+[\s]{1}[A-za-z]+)|([A-Za-z]+))$",ErrorMessage = "Only upper and lower case alphabets are allowed")]
        [StringLength (10,MinimumLength =5)]
        public string Name { get; set; }
   


Compare Attribute


Compare attribute is used to compare 2 properties of a model. 




   [MetadataType(typeof(EmployeeMetaData))]
   public partial class Employee
   {
     [Compare("Name")]
     public string confirmName { get; set; }
   }
 
   public class EmployeeMetaData
   {
       [RegularExpression(@"^(([A-za-z]+[\s]{1}[A-za-z]+)|([A-Za-z]+))$",ErrorMessage = "Only upper and lower case alphabets are allowed")]
       [StringLength (10,MinimumLength =5)]
 
       public string Name { get; set; }
   }


Required Attribute


This is used to enforce the property is required 




    [MetadataType(typeof(EmployeeMetaData))]
    public partial class Employee
    {
      
    }
 
    public class EmployeeMetaData
    {
        [Required]
        public string Name { get; set; }
 
        [Required]
        public string Designation { get; set; }
    }


Display Attribute


This is used to display change the caption (Overrides auto generated name)




[MetadataType(typeof(DepartmentMetaData))]
public partial class Department
{
}

public class DepartmentMetaData
{
    [Display(Name="Department Name")]
    public string Name { get; set; }
}





DisplayName Attribute


Namespace: using System.ComponentModel;



        [DisplayName("Employee Name")]
        public string Name { get; set; }



DispalyAttribute Attribute



       [DisplayAttribute(Name="Employee Name")]
       public string Name { get; set; }


DisplayFormat Attribute


 If gender is NULL, "Gender not specified" text will be displayed.

    [DisplayFormat(NullDisplayText = "Gender not specified")]
        public string Gender { get; set; }



ScaffoldColumn Attribute



If you don't want to display a column use ScaffoldColumn attribute. This only works when you use @Html.DisplayForModel() helper


        [ScaffoldColumn(false)]
        public int? Salary { get; set; }







datatype Attribute




Used to specify specific data type in the model.





    [DataType(DataType.EmailAddress)]
    public string EmailAddress { get; set; }





    [DataType(DataType.Currency)]
    public int? Salary { get; set; }




    [DataType(DataType.Url)]
    public string PersonalWebSite { get; set; }




    [DataType(DataType.Date)]
    public DateTime? HireDate { get; set; }