Update 2007/05/07: There is also a Microsoft MapPoint v4.5 project I've written that does the same thing. Click here to go to that post.

Retrieve the Latitude and Longitude of any addresses in the United States, Canada, France, Germany, Italy, Spain and Japan (link) with this class. View the class below and download the class at the bottom of this post.

Code

using System;
using System.Collections.Generic;
using System.Text;
using System.Web;
using System.Net;
using System.Web.UI;


namespace GoogleGeocoder
{
   public interface ISpatialCoordinate
   {
      decimal Latitude {get; set; } 
      decimal Longitude {get; set; } 
   }

   /// <summary>
   /// Coordiate structure. Holds Latitude and Longitude.
   /// </summary>
   public struct Coordinate : ISpatialCoordinate
   {
      private decimal _latitude; 
      private decimal _longitude;

      public Coordinate(decimal latitude, decimal longitude)
      {
         _latitude = latitude;
         _longitude = longitude; 
      }

      #region ISpatialCoordinate Members

      public decimal Latitude
      {
        get 
        { 
            return _latitude; 
        }
        set 
        { 
            this._latitude = value; 
        }
      }

      public decimal Longitude
      {
        get 
        { 
            return _longitude; 
        }
        set 
        { 
            this._longitude = value;
        }
      }

   #endregion
   }

   public class Geocode
   {
      private const string _googleUri = "http://maps.google.com/maps/geo?q=";
      private const string _googleKey = "yourkey";
      private const string _outputType = "csv"; // Available options: csv, xml, kml, json

      private static Uri GetGeocodeUri(string address)
      {
         address = HttpUtility.UrlEncode(address);
         return new Uri(String.Format("{0}{1}&output={2}&key={3}", _googleUri, address, _outputType, _googleKey));
      }

      /// <summary>
      /// Gets a Coordinate from a address.
      /// </summary>
      /// <param name="address">An address.
      /// <remarks>
      /// <example>1600 Amphitheatre Parkway Mountain View, CA 94043</example>
      /// </remarks>
      /// </param>
      /// <returns>A spatial coordinate that contains the latitude and longitude of the address.</returns>
      public static Coordinate GetCoordinates(string address)
      {
         WebClient client = new WebClient();
         Uri uri = GetGeocodeUri(address);


         /* The first number is the status code, 
         * the second is the accuracy, 
         * the third is the latitude, 
         * the fourth one is the longitude.
         */
         string[] geocodeInfo = client.DownloadString(uri).Split(',');

         return new Coordinate(Convert.ToDecimal(geocodeInfo[2]), Convert.ToDecimal(geocodeInfo[3]));
      }

   }
}

How To Use

1. Replace "yourkey" with your google api key. Get one here.
2. Include in your project, reference the class through a using directive.
3. Call get the coordinates like this:

   1. Coordinate coordinate = Geocode.GetCoordinates("1600 Amphitheatre Parkway Mountain View, CA 94043");
      decimal latitude = coordinate.Latitude;
      decimal longitude = coordinate.Longitude;

Uses

***Notes***

The maximum # of Geocode requests that can be completed in one day are 50,000 (details).

Download
Geocode.zip (1.05 KB)