To set the desired value into Dropdown box, the below piece of would work fine!
                                                                                                         
using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using OpenQA.Selenium;
using OpenQA.Selenium.IE;
//add this name space to access WebDriverWait
using OpenQA.Selenium.Support.UI;
namespace AutomationUsingSelenium
{
    class Program
    {
        public static InternetExplorerDriver WebDriver;
        static void Main(string[] args)
        {                     
        var capabilitiesInternet = new OpenQA.Selenium.Remote.DesiredCapabilities();
        capabilitiesInternet.SetCapability("ignoreProtectedModeSettings", true);
        WebDriver = new InternetExplorerDriver(capabilitiesInternet);
        WebDriver.Navigate().GoToUrl("http://www.x-rates.com/calculator.html");
 //Get the hold of the dropdown box by Name 
 IWebElement setValueConvert = WebDriver.FindElement(By.Name("from")); 
//Place the drop down into selectElemnet 
 SelectElement clickThisitem=new SelectElement(setValueConvert); 
 Thread.Sleep(600); 
//Select the Item from dropdown by Index 
 clickThisitem.SelectByIndex(12); 
//Select the Item from dropdown by Text 
 clickThisitem.SelectByText("EUR"); 
 | 
         }
    }
}
Wesite Under Test:
Thanks,
Md. Jawed
