How to create Custom Data Annotations using MVC 4 application with client validation
Step 1 : create mvc application .
Step 2 : Add one entity class "Employee"
public class Employee
{
public int RollNumber { get; set; }
public string StudentName { get; set; }
public int Age { get; set; }
public string Sem { get; set; }
public string EmailAddress { get; set; }
public int Year { get; set; }
}
Step 3 : Create .cshtml file of Employee creation.
Step 4 : Add one class file of creation of CustomValidationAttribute
Step 5 : Paste below code in that file.
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Text.RegularExpressions;
using System.Web.Mvc;
namespace MVC_Custom_DataAnnotations
{
public class CustomRangeAttribute : RangeAttribute, IClientValidatable
{
private double _Minimum;
private double _Maximum;
private string _message;
public CustomRangeAttribute(double minimum, double maximum, string message)
: base(minimum, maximum)
{
_Minimum = minimum;
_Maximum = maximum;
_message = message;
}
public override bool IsValid(object value)
{
if (value == null)
{
return true;
}
double valueObject;
Double.TryParse(Convert.ToString(value), out valueObject);
return _Minimum <= valueObject && valueObject <= _Maximum;
}
public override string FormatErrorMessage(string name)
{
return _message;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
var rule = new ModelClientValidationRule();
rule.ErrorMessage = FormatErrorMessage(metadata.GetDisplayName());
rule.ValidationParameters.Add("range", string.Format("{0}~{1}", Minimum, Maximum));
rule.ValidationType = "customrange";
yield return rule;
}
}
public class CustomStringLengthAttribute : StringLengthAttribute, IClientValidatable
{
public int MaximumLength;
public string message;
public string KeyName;
public CustomStringLengthAttribute(int maximumLength, string errormessage)
: base(maximumLength)
{
MaximumLength = maximumLength;
message = errormessage;
}
public override bool IsValid(object value)
{
if (value == null)
{
return true;
}
int valueObject = Convert.ToString(value).Length;
return valueObject <= MaximumLength;
}
public override string FormatErrorMessage(string name)
{
return message;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
var rule = new ModelClientValidationRule();
rule.ErrorMessage = FormatErrorMessage(metadata.GetDisplayName());
rule.ValidationParameters.Add("maximumlength", MaximumLength);
rule.ValidationType = "customstringlength";
yield return rule;
}
}
public class CustomRegularExpressionAttribute : RegularExpressionAttribute, IClientValidatable
{
private string Pattern;
private string message;
public CustomRegularExpressionAttribute(string pattern, string errorMessage)
: base(pattern)
{
Pattern = pattern;
message = errorMessage;
}
public override bool IsValid(object value)
{
if (value == null)
{
return true;
}
Match match = Regex.Match(Convert.ToString(value), Pattern, RegexOptions.IgnoreCase);
return match.Success;
}
public override string FormatErrorMessage(string name)
{
return message;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
var rule = new ModelClientValidationRule();
rule.ErrorMessage = FormatErrorMessage(metadata.GetDisplayName());
rule.ValidationParameters.Add("pattern", Pattern);
rule.ValidationType = "customregularexpression";
yield return rule;
}
}
}
Step 6 : Now add attribute to Employee class object.
public class Employee
{
public int RollNumber { get; set; }
public string StudentName { get; set; }
[CustomRangeAttribute(1, 100, "Age between 1 to 100")]
public int Age { get; set; }
[CustomStringLengthAttribute(5, "Maximum char allowed in sem field is 5.")]
[DataMember]
public string Sem { get; set; }
[CustomRegularExpressionAttribute("^[A-Za-z0-9_\\+-]+(\\.[A-Za-z0-9_\\+-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*\\.([A-Za-z]{2,4})$", "Please enter valid email address.")]
public string EmailAddress { get; set; }
[CustomRangeAttribute(1950, 2014, "Year between 1950 to 2014")]
public int Year { get; set; }
}
Step 8 : Add code for checking server side validation.
[HttpPost]
public ActionResult Create(Employee emp)
{
try
{
if (!ModelState.IsValid)
{
return View(emp);
}
return RedirectToAction("Index");
}
catch
{
return View();
}
}
Step 9 : Run your application and try to produce the error using invalid value.
Step 10 : This way you can create custom validation for server side.
Watch video for visual explanation on this point.
https://www.youtube.com/watch?v=-t1EemDasMc&feature=youtu.be
