SPFieldUrlValue class

[SerializableAttribute]
[SubsetCallableTypeAttribute]
[ClientCallableTypeAttribute(Name = "FieldUrlValue", ValueObject = true, ServerTypeId = "{FA8B44AF-7B43-43f2-904A-BD319497011E}")]
public class SPFieldUrlValue

using System;
using Microsoft.SharePoint;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            using (SPSite site = new SPSite("http://localhost"))
            {
                using (SPWeb web = site.OpenWeb("test"))
                {
                    // Get the Links list or create it if it does not exist.
                    SPList list = web.Lists.TryGetList("Links");

                    if (list == null || list.BaseTemplate != SPListTemplateType.Links)
                    {
                        // Create the list.
                        Guid listId = web.Lists.Add("Links", "A list of interesting Web pages.", SPListTemplateType.Links);
                        list = web.Lists.GetList(listId, false);
                    }

                    // Create a link field value.
                    SPFieldUrlValue msdnValue = new SPFieldUrlValue();
                    msdnValue.Description = "SharePoint Developer Center";
                    msdnValue.Url = "http://msdn.microsoft.com/sharepoint";

                    // Print the field value.
                    Console.WriteLine(msdnValue);
                    
                    // Check if the list already has this link.
                    SPListItem msdnItem = null;
                    foreach (SPListItem item in list.Items)
                    {
                        Object rawValue = item[SPBuiltInFieldId.URL];
                        SPFieldUrlValue typedValue = new SPFieldUrlValue(rawValue.ToString());
                        if (typedValue.Url == msdnValue.Url)
                        {
                            msdnItem = item;
                            Console.WriteLine("Existing link.");
                            continue;
                        }
                    }

                    // If it does not...
                    if (msdnItem == null)
                    {
                        // Create a new list item and set the URL field value.
                        msdnItem = list.Items.Add();
                        msdnItem[SPBuiltInFieldId.URL] = msdnValue;
                        msdnItem.Update();

                        Console.WriteLine("Link added.");
                    }
                }
            }
            Console.Write("\nPress ENTER to continue....");
            Console.ReadLine();
        }
    }
}