using System;
using System.ComponentModel.DataAnnotations;

namespace MvcApplication9.Models
{
    public class Customer
    {
        public int Id { set; get; }

        [Required(ErrorMessage = "Name is required.")]
        [StringLength(50)]
        public string Name { set; get; }

        [Display(Name = "Email address")]
        [Required(ErrorMessage = "Email address is required.")]
        [RegularExpression(@"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*",
                           ErrorMessage = "Please enter a valid email address.")]
        public string Email { set; get; }

        [Range(0, 10)]
        [Required(ErrorMessage = "Rating is required.")]
        public double Rating { set; get; }

        [Display(Name = "Start date")]
        [Required(ErrorMessage = "Start date is required.")]
        public DateTime StartDate { set; get; }
    }
}

using System.Web.Mvc;
using MvcApplication9.Models;

namespace MvcApplication9.Controllers
{
    public class CustomerController : Controller
    {
        [HttpGet]
        public ActionResult Create()
        {
            var customer = new Customer();
            return View(customer);
        }

        [HttpPost]
        public ActionResult Create(Customer customer)
        {
            if (this.ModelState.IsValid)
            {
                //todo: save data
                return Redirect("/");
            }
            return View(customer);
        }
    }
}

<appSettings>
    <add key="ClientValidationEnabled" value="true"/>

@{ Html.EnableClientValidation(false); }

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>Customer</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.Name)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Name)
            @Html.ValidationMessageFor(model => model.Name)
        </div>

<input data-val="true" data-val-required="The Birthday field is required." id="Birthday" name="Birthday" type="text" value="" />

<script src="../../Scripts/customvaildation.js" type="text/javascript"></script>

using System;
using System.ComponentModel.DataAnnotations;

namespace MvcApplication9.CustomValidators
{
    public class MyDateValidator : ValidationAttribute
    {
        public int MinYear { set; get; }

        public override bool IsValid(object value)
        {
            if (value == null) return false;

            var date = (DateTime)value;
            if (date > DateTime.Now || date < new DateTime(MinYear, 1, 1))
                return false;

            return true;
        }
    }
}

[Display(Name = "Start date")]
[Required(ErrorMessage = "Start date is required.")]
[MyDateValidator(MinYear = 2000,
                         ErrorMessage = "Please enter a valid date.")]
public DateTime StartDate { set; get; }

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using MvcApplication9.CustomValidators;

namespace MvcApplication9.Models
{
    public class Customer : IValidatableObject
    {
        //... same as before

        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
        {
            var fields = new[] { "StartDate" };
            if (StartDate > DateTime.Now || StartDate < new DateTime(2000, 1, 1))
                yield return new ValidationResult("Please enter a valid date.", fields);

            if (Rating > 4 && StartDate < new DateTime(2003, 1, 1))
                yield return new ValidationResult("Accepted date should be greater than 2003", fields);
        }
    }
}

protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
    var info = validationContext.ObjectType.GetProperty("Rating");
    //...
    return ValidationResult.Success;
}

using System;
using System.ComponentModel.DataAnnotations;
using System.Web.Mvc;
using System.Collections.Generic;

namespace MvcApplication9.CustomValidators
{
    public class MyDateValidator : ValidationAttribute, IClientValidatable
    {
       // ... same as before

        public IEnumerable<ModelClientValidationRule> GetClientValidationRules(
                    ModelMetadata metadata, 
                    ControllerContext context)
        {
            var rule = new ModelClientValidationRule
            {
                ValidationType = "mydatevalidator",
                ErrorMessage = FormatErrorMessage(metadata.GetDisplayName())
            };
            yield return rule;
        }
    }
}

/// <reference path="jquery-1.5.1-vsdoc.js" />
/// <reference path="jquery.validate-vsdoc.js" />
/// <reference path="jquery.validate.unobtrusive.js" />

jQuery.validator.addMethod("mydatevalidator",
 function (value, element, param) {
     return Date.parse(value) < new Date();
});

jQuery.validator.unobtrusive.adapters.addBool("mydatevalidator");

<script src="@Url.Content("~/Scripts/customvaildation.js")" type="text/javascript"></script>

1. .field-validation-error
2. .field-validation-valid
3. .input-validation-error
4. .input-validation-valid
5. .validation-summary-errors
6. .validation-summary-valid

[MetadataType(typeof(CustomerMetadata))]
public partial class Customer
{
    class CustomerMetadata
     {

     }
}

public partial class Customer : IValidatableObject
{

[Required(ErrorMessage = "Name is required.")]
[StringLength(50)]
[System.Web.Mvc.Remote(action: "CheckUserNameAndEmail",
                               controller: "Customer",
                               AdditionalFields = "Email",
                               HttpMethod = "POST",
                               ErrorMessage = "Username is not available.")]
public string Name { set; get; }

[HttpPost]
[OutputCache(Location = OutputCacheLocation.None, NoStore = true)]
public ActionResult CheckUserNameAndEmail(string name, string email)
{
      if (name.ToLowerInvariant() == "vahid") return Json(false);
      if (email.ToLowerInvariant() == "name@site.com") return Json(false);
      //...
      return Json(true);
}

using System.ComponentModel.DataAnnotations;

namespace MvcApplication9.Helper
{
    public static class ValidationHelper
    {
        public static bool TryValidateObject(this object instance)
        {
            return Validator.TryValidateObject(instance, new ValidationContext(instance, null, null), null);
        }
    }
}

CREATE TABLE Products (
product_id SERIAL PRIMARY KEY,
product_name VARCHAR(1000),
account_id BIGINT UNSIGNED,
-- . . .
FOREIGN KEY (account_id) REFERENCES Accounts(account_id)
);

INSERT INTO Products (product_id, product_name, account_id)
VALUES (DEFAULT, 'Visual TurboBuilder' , 12);

namespace WpfViewModelLocator.ViewModels
{
    public class MainWindowViewModel
    {
        public string SomeText { set; get; }
        public MainWindowViewModel()
        {
            SomeText = "Data ...";
        }
    }
}

using WpfViewModelLocator.ViewModels;

namespace WpfViewModelLocator.ViewModelLocator
{
    public class ViewModelLocatorBase
    {
        public MainWindowViewModel MainWindowVm
        {
            get { return new MainWindowViewModel(); }
        }
    }
}

<Application x:Class="WpfViewModelLocator.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:vml="clr-namespace:WpfViewModelLocator.ViewModelLocator"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <vml:ViewModelLocatorBase x:Key="ViewModelLocatorBase" />
    </Application.Resources>
</Application>

<Window x:Class="WpfViewModelLocator.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        
        Title="MainWindow" Height="350" Width="525">
    <Grid DataContext="{Binding Path=MainWindowVm, Source={StaticResource ViewModelLocatorBase}}">
        <TextBlock Text="{Binding SomeText}" VerticalAlignment="Top" Margin="5" />
    </Grid>
</Window>

using System;
using System.Globalization;
using System.Linq;
using System.Windows.Data;

namespace WpfViewModelLocator.ViewModelLocator
{
    public class ViewModelLocatorBaseConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            //مقدار در اینجا همان مشخصات ویوو است
            if (value == null) return null;
            string viewTypeName = value.GetType().Name;

            //قرار داد ما است
            //ViewModel Name = ViewName + "ViewModel"
            string viewModelName = string.Concat(viewTypeName, "ViewModel");

            //یافتن اسمبلی که حاوی ویوو مدل ما است
            var asms = AppDomain.CurrentDomain.GetAssemblies();
            var viewModelAsmName = "WpfViewModelLocator"; //نام پروژه مرتبط
            var viewModelAsm = asms.Where(x => x.FullName.Contains(viewModelAsmName)).First();

            //یافتن این کلاس ویوو مدل مرتبط
            var viewModelType = viewModelAsm.GetTypes().Where(x => x.FullName.Contains(viewModelName)).FirstOrDefault();
            if (viewModelType == null)
                throw new InvalidOperationException(string.Format("Could not find view model '{0}'", viewModelName));

            //وهله سازی خودکار آن
            return Activator.CreateInstance(viewModelType);
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

<Application x:Class="WpfViewModelLocator.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:vml="clr-namespace:WpfViewModelLocator.ViewModelLocator"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <vml:ViewModelLocatorBaseConverter x:Key="ViewModelLocatorBaseConverter" />
    </Application.Resources>
</Application>

<Window x:Class="WpfViewModelLocator.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"                
        DataContext="{Binding RelativeSource={RelativeSource Self}, 
                              Converter={StaticResource ViewModelLocatorBaseConverter}}"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TextBlock Text="{Binding SomeText}" VerticalAlignment="Top" Margin="5" />
    </Grid>
</Window>

 @RenderPage("~/views/path/_partial_view.cshtml", new { Employee = grid.SelectedRow })

public class PropertiesValidator<TK, T> where T : new() where TK : new()
{
    static TK _instance;

    public static TK Instance
    {
        get
        {
            if (_instance == null)
            {
                _instance = new TK();
            }
            return _instance;
        }
    }

    public void Validate(T expectedObject, T realObject, params string[] propertiesNotToCompare)
    {
        var properties = realObject.GetType().GetProperties();
        foreach (var currentRealProperty in properties)
        {
            if (!propertiesNotToCompare.Contains(currentRealProperty.Name))
            {
                var currentExpectedProperty = expectedObject.GetType().GetProperty(currentRealProperty.Name);
                var exceptionMessage = $"The property {currentRealProperty.Name} of class {currentRealProperty.DeclaringType?.Name} was not as expected.";

                if (currentRealProperty.PropertyType != typeof(DateTime) && currentRealProperty.PropertyType != typeof(DateTime?))
                {
                    Assert.AreEqual( currentExpectedProperty.GetValue( expectedObject,
                                                                        null ),
                                        currentRealProperty.GetValue( realObject,
                                                                    null ),
                                        exceptionMessage );
                }
                else
                {
                    DateTimeAssert.Validate( currentExpectedProperty.GetValue( expectedObject,
                                                                                null ) as DateTime?,
                                                currentRealProperty.GetValue( realObject,
                                                                            null ) as DateTime?,
                                                TimeSpan.FromMinutes( 5 ) );
                }
            }
        }
    }
}

public class ObjectToAssert
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public DateTime LastVisit { get; set; }
}

var expectedObject = new ObjectToAssert
                        {
                            FirstName = "Vahid",
                            LastName = "Mohammad Taheri",
                            LastVisit = new DateTime( 2016, 11, 14, 0, 10, 50 )
                        };
var actualObject = new ObjectToAssert
                        {
                            FirstName = "Vahid",
                            LastName = "Mohammad Taheri",
                            LastVisit = new DateTime( 2016, 11, 14, 0, 13, 50 )
                        };