AsEnumerable() in Linq

AsEnumerable() method in Linq is used to cast or convert given type into it's IEnumerable type. AsEnumerable() basically changes the compile time type of given type that implements IEnumerable to IEnumerable itself.

Sample code to use AsEnumerable() in Linq

 protected void Page_Load(object sender, EventArgs e)
  {
      var numArray = new int[5];
      numArray[0] = 5;
      numArray[1] = 10;
      numArray[2] = 7;
      numArray[3] = 9;
      numArray[4] = 1;

      var numbers = numArray.AsEnumerable();
      foreach (var number in numbers)
       {
          Console.WriteLine(number);
       }
  }

Convert ToList() in Linq

In C# Linq, there is .ToList() extension method that is used to convert IEnumerable to List of type. Like .ToArray(), ToList() also forces immediate query execution and stores query result in List.

Example that shows how to convert array to list

 protected void Page_Load(object sender, EventArgs e)
  {
     string[] language = { "C#", "C++", "Java", "Pascal", "Cobol" };
     List languageList = language.ToList();

     foreach (string lang in languageList)
     {
                Console.WriteLine(lang);
     }
  }

Convert ToArray in linq

In C# while using Linq, we have .ToArray() extension method that is used to convert IEnumerable to an array. .ToArray() forces immediate query execution and stores query result in an array.

Example of Linq .ToArray()

 public partial class LinqToArray : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

            var carslist =
                new List 
                        { new Cars { Company = "Maruti Suzuki", Average = 15.2 },
                          new Cars { Company = "Mercedes", Average = 18.7 },
                          new Cars { Company = "Volvo", Average = 20.0 },
                          new Cars { Company = "Hundai", Average = 12.8 } };

            var companies = carslist.Where(c => c.Average > 15)
                                         .Select(c => c.Company)
                                         .ToArray();

            foreach (var company in companies)
            {
                Console.WriteLine(company);
            }
        }

    public class Cars
    {
        public string Company { get; set; }
        public double Average { get; set; }
    }

Output:
   /*
     //Maruti Suzuki
     // Mercedes
     // Volvo
   */

In above sample code we have converted List to array using linq.

ASP.NET CompareValidator

In this post we will see how to use compare validator to compare the two input values. Using compare validator we can compare two values from two different input controls or we can compare input value with some constant or fixed value.

Example of compare validator

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <ul style="list-style-type: none">
            <li>
                <asp:TextBox ID="txt1" runat="server" />
                =
                <asp:TextBox ID="txt2" runat="server" />
            </li>
            <li>
                <asp:Button ID="Button1" Text="Validate" runat="server" />
            </li>
        </ul>
        <br>
        <asp:CompareValidator ID="compareval" Display="dynamic" ControlToValidate="txt1"
            ControlToCompare="txt2" ForeColor="red" Type="String" EnableClientScript="false"
            Text="Values are not equal." runat="server" />
    </div>
    </form>
</body>
</html>

So in compare validator we need to set ControlToValidate and ControlToCompare in order to compare two input values.