Here’s the ASP.NET code for this utility. Don’t forget to install the FlickrNet library from http://flickrnet.codeplex.com and set a reference to the .dll within the project.

using FlickrNet; 

public partial class localpic : System.Web.UI.Page
    {
        private Location _Location; // Holds location information 

        // Load page, show initial pictures from city based on IP location services
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                _Location = new Location(Request);

                // This class interacts with 3rd party library FlickrNet (http://flickrnet.codeplex.com/)
                techyFlikr tf = new techyFlikr();

                // Set city label and insert into dropdown if it doesn't already exist

                if (_Location._oLocation.City.Length != 0)
                {
                    lblCity.Text = _Location._oLocation.City;
                }

                ddlCities.DataSourceID = "dsCities";
                ddlCities.DataBind();
                if (!(ddlCities.Items.Contains(new ListItem(lblCity.Text))))
                {
                    ddlCities.Items.Insert(0, _Location._oLocation.City.ToString());
                }
                ddlCities.Visible = true;
                Session["loc"] = _Location;

                // When page is loaded, display pictures from nearest geolocated city

                if (_Location._oLocation.City.Length != 0)
                {
                    gvPictures.DataSource = tf.getPhotos(_Location, ddlCities.SelectedValue.ToString()); ;
                    gvPictures.DataBind();
                }
            }
            _Location = (Location)Session["loc"];
        }

        // User has selected a city, show pictures for item selected

        protected void ddlCities_SelectedIndexChanged(object sender, EventArgs e)
        {
            techyFlikr tf = new techyFlikr();
            // Get photos from Flickr service and bind to grid
            gvPictures.DataSource = tf.getPhotos(_Location, ddlCities.SelectedValue.ToString()); ;
            gvPictures.DataBind();
         }

        // User wants to see more pictures from selected city

        protected void Button1_Click(object sender, EventArgs e)
        {
            techyFlikr tf = new techyFlikr();
            gvPictures.DataSource = tf.getPhotos(_Location, ddlCities.SelectedValue.ToString()); ;
            gvPictures.DataBind();
         }

    }

The code for the techyFlickr class is below:

    public class techyFlikr
    {
        FlickrNet.Flickr _oFlikr = new FlickrNet.Flickr(" API goes here");

        // Get pictures from service and return a List of Photos

        public List getPhotos(Location loc, String sCity)
        {
            // Pick a random page between 1 and 40
            Random rnd = new Random();
            int page = rnd.Next(1, 40);

            PhotoSearchOptions searchOptions = new PhotoSearchOptions();
            searchOptions.Tags = sCity;  // use the selected city as search tag
            searchOptions.PerPage = 15;
            searchOptions.Page = page;
            if (sCity.Length == 0)
            {
                searchOptions.Tags = "New York";  // default to New York if no city found
            }

            // Perform the search and return collection of Photo objects
            PhotoCollection photos = _oFlikr.PhotosSearch(searchOptions);

            List allPhotos = new List();
            allPhotos.AddRange(photos);
            return allPhotos;
        }
    }

Here’s the class definitions for the Location service which shows how to deserialize a JSON response into a .NET object.

    // Class to hold data from Response
    public class myLocationJson
    {
        public string Ip { get; set; }
        public string Status { get; set; }
        public string CountryCode { get; set; }
        public string RegionCode { get; set; }
        public string RegionName { get; set; }
        public string City { get; set; }
        public string ZipPostalCode { get; set; }
        public string Latitude { get; set; }
        public string Longitude { get; set; }
    }

    public class Location
    {
        // Holds JSON data from location service

        public myLocationJson _oLocation = new myLocationJson();
        public string sMessage = string.Empty;

        public Location(HttpRequest request)
        {
            try
            {
                // Get location from the IP browser address using a JSON web service
                WebRequest myRequest = WebRequest.Create("http://ipinfodb.com/ip_query.php?ip=" +
                                        request.UserHostAddress + "&output=json&timezone=false");
                WebResponse myResponse = (WebResponse)myRequest.GetResponse();
                String sLocation = string.Empty;
                String sCity = string.Empty;

                // Read web response into string

                using (StreamReader sr = new StreamReader(myResponse.GetResponseStream()))
                { sLocation = sr.ReadToEnd(); }

                // Read JSON response into our custom class to get properties
                JavaScriptSerializer ser = new JavaScriptSerializer();
                _oLocation = ser.Deserialize(sLocation);
            }
            catch (Exception ex)
            {
                sMessage = ex.Message;
                _oLocation.Ip = string.Empty;
            }
        }
    }