namespace IOCBeginnerGuide
{
  class Kid
  {
      private int _age;
      private string _name;

      public Kid(int age, string name)
      {
          _age = age;
          _name = name;
      }

      public override string ToString()
      {
          return "KID's Age: " + _age + ", Kid's Name: " + _name;
      }
  }
}

using System;

namespace IOCBeginnerGuide
{
  class Parent
  {
      private int _age;
      private string _name;
      private Kid _obj;

      public Parent(int personAge, string personName, int kidsAge, string kidsName)
      {
          _obj = new Kid(kidsAge, kidsName);
          _age = personAge;
          _name = personName;
      }

      public override string ToString()
      {
          Console.WriteLine(_obj);
          return "ParentAge: " + _age + ", ParentName: " + _name;
      }
  }
}

using System;

namespace IOCBeginnerGuide
{
  class Program
  {
      static void Main(string[] args)
      {
          Parent p = new Parent(35, "Dev", 6, "Len");
          Console.WriteLine(p);

          Console.ReadKey();
          Console.WriteLine("Press a key...");
      }
  }
}

KID's Age: 6, Kid's Name: Len
ParentAge: 35, ParentName: Dev

//IBuisnessLogic.cs
namespace IOCBeginnerGuide
{
  public interface IBuisnessLogic
  {
  }
}

//Kid.cs
namespace IOCBeginnerGuide
{
  class Kid : IBuisnessLogic
  {
      private int _age;
      private string _name;

      public Kid(int age, string name)
      {
          _age = age;
          _name = name;
      }

      public override string ToString()
      {
          return "KID's Age: " + _age + ", Kid's Name: " + _name;
      }
  }
}

//Parent.cs
using System;

namespace IOCBeginnerGuide
{
  class Parent
  {
      private int _age;
      private string _name;
      private IBuisnessLogic _refKids;

      public Parent(int personAge, string personName, IBuisnessLogic obj)
      {          
          _age = personAge;
          _name = personName;
          _refKids = obj;
      }

      public override string ToString()
      {
          Console.WriteLine(_refKids);
          return "ParentAge: " + _age + ", ParentName: " + _name;
      }
  }
}

//CIOC.cs
using System;

namespace IOCBeginnerGuide
{
  class CIOC
  {
      Parent _p;

      public void FactoryMethod()
      {
          IBuisnessLogic objKid = new Kid(12, "Ren");
          _p = new Parent(42, "David", objKid);
      }

      public override string ToString()
      {
          Console.WriteLine(_p);          
          return "Displaying using Constructor Injection";
      }
  }
}

//Program.cs
using System;

namespace IOCBeginnerGuide
{
  class Program
  {
      static void Main(string[] args)
      {
          CIOC obj = new CIOC();
          obj.FactoryMethod();
          Console.WriteLine(obj);

          Console.ReadKey();
          Console.WriteLine("Press a key...");
      }
  }
}

//Parent.cs
using System;

namespace IOCBeginnerGuide
{
  class Parent
  {
      private int _age;
      private string _name;

      public Parent(int personAge, string personName)
      {          
          _age = personAge;
          _name = personName;
      }

      public IBuisnessLogic RefKID {set; get;}

      public override string ToString()
      {
          Console.WriteLine(RefKID);
          return "ParentAge: " + _age + ", ParentName: " + _name;
      }
  }
}

//CIOC.cs
using System;

namespace IOCBeginnerGuide
{
  class CIOC
  {
      Parent _p;

      public void FactoryMethod()
      {
          IBuisnessLogic objKid = new Kid(12, "Ren");
          _p = new Parent(42, "David");
          _p.RefKID = objKid;
      }

      public override string ToString()
      {
          Console.WriteLine(_p);          
          return "Displaying using Setter Injection";
      }
  }
}

using System;
using System.Collections.Generic;
using System.Linq;

namespace testWinForms87
{
  public class Data
  {
      public int id { get; set; }
      public string name { get; set; }
  }

  class CLinqTests
  {
      public static int TestGetListMin1()
      {
          var lst = new List<Data>
          {
                  new Data{ id=1, name="id1"},
                  new Data{ id=2, name="id2"},
                  new Data{ id=3, name="name3"}
          };

          return (from c in lst
                  where c.name.Contains("id")
                  select c.id).Min();
      }
    
      public static int TestGetListMin2()
      {
          var lst = new List<Data>();

          return (from c in lst
                  where c.name.Contains("id")
                  select c.id).Min();
      }
  }
}

      public static int TestGetListMin3()
      {
          var lst = new List<Data>();
          var query = from c in lst
                      where c.name.Contains("id")
                      select c.id;

          if (query.Any())
              return query.Min();
          else
              return -1;
      }

using System;
using System.Collections.Generic;
using System.Linq;

  public static class LinqExtensions
  {
      public static T MinOrDefault<T>(this IEnumerable<T> source, T defaultValue)
      {
          if (source.Any<T>())
              return source.Min<T>();

          return defaultValue;
      }

      public static T MaxOrDefault<T>(this IEnumerable<T> source, T defaultValue)
      {
          if (source.Any<T>())
              return source.Max<T>();

          return defaultValue;
      }
  }

      public static int TestGetListMin4()
      {
          var lst = new List<Data>();
          return (from c in lst
                  where c.name.Contains("id")
                  select c.id).MinOrDefault(-1);
      }

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);
        }
    }
}

public class Browser
{
    public int Id { get; set; }
    public string Engine { get; set; }
    public string Name { get; set; }
    public string Platform { get; set; }
    public float Version { get; set; }
    public string Grade { get; set; }
}

public static List<T> RemoveDuplicates<T>(List<T> items)
{
   return (from s in items  select s).Distinct().ToList();
}

public static void TestRemoveDuplicates()
{
   List<string> sampleList =
       new List<string>() { "A1", "A2", "A3", "A1", "A2", "A3" };
   sampleList = RemoveDuplicates(sampleList);
   foreach (var item in sampleList)
       Console.WriteLine(item);
}

public class Employee
{
   public int ID { get; set; }
   public string FName { get; set; }
   public int Age { get; set; }
}

public static void TestRemoveDuplicates()
{
   List<Employee> lstEmp = new List<Employee>()
   {
      new  Employee(){ ID=1, Age=20, FName="F1"},
      new  Employee(){ ID=2, Age=21, FName="F2"},
      new  Employee(){ ID=1, Age=20, FName="F1"},
   };

   lstEmp = RemoveDuplicates<Employee>(lstEmp);

   foreach (var item in lstEmp)
       Console.WriteLine(item.FName);
}

public static IEnumerable<TSource> Distinct<TSource>(this IEnumerable<TSource> source, IEqualityComparer<TSource> comparer);

public class EmployeeComparer : IEqualityComparer<Employee>
{
 public bool Equals(Employee x, Employee y)
 {
   //آیا دقیقا یک وهله هستند؟
   if (Object.ReferenceEquals(x, y)) return true;

   //آیا یکی از وهله‌ها نال است؟
   if (Object.ReferenceEquals(x, null) ||
       Object.ReferenceEquals(y, null))
       return false;

   return x.Age == y.Age && x.FName == y.FName && x.ID == y.ID;
 }

 public int GetHashCode(Employee obj)
 {
   if (Object.ReferenceEquals(obj, null)) return 0;
   int hashTextual = obj.FName == null ? 0 : obj.FName.GetHashCode();
   int hashDigital = obj.Age.GetHashCode();
   return hashTextual ^ hashDigital;
 }
}

public static List<T> RemoveDuplicates<T>(List<T> items, IEqualityComparer<T> comparer)
{
   return (from s in items select s).Distinct(comparer).ToList();
}

public static void TestRemoveDuplicates()
{
   List<Employee> lstEmp = new List<Employee>()
   {
      new  Employee(){ ID=1, Age=20, FName="F1"},
      new  Employee(){ ID=2, Age=21, FName="F2"},
      new  Employee(){ ID=1, Age=20, FName="F1"},
   };

   lstEmp = RemoveDuplicates(lstEmp, new EmployeeComparer());

   foreach (var item in lstEmp)
       Console.WriteLine(item.FName);
}

public static void FindDuplicates()
{
   List<Employee> lstEmp = new List<Employee>()
   {
      new  Employee(){ ID=1, Age=20, FName="F1"},
      new  Employee(){ ID=2, Age=21, FName="F2"},
      new  Employee(){ ID=1, Age=20, FName="F1"},
   };

   var query = from c in lstEmp
               group c by c.Age into g
               where g.Count() > 1
               select new { Age = g.Key, Count = g.Count() };

   foreach (var item in query)
   {
       Console.WriteLine("Age {0} has {1} records", item.Age, item.Count);
   }
}