Is it possible to get the longitude and latitude value from IP address in asp.net? If it is possible, please let me know how can I get this.
MaxMind Geolite city is free. If it is not good enough, you can apparently upgrade to a more accurate paid-version. I can't speak for the quality of the paid version, as I have never used it.
If you like your SQL, download the CSV version. Load it into your database of choice, and query away.
The faster and space-efficient option is to download the file binary blob version of the same database, and then use the C# class to query it.
Alternatively, I have found ipinfodb.com to be useful. Query is by simple HTTP GET. For example, to geolocate stackoverflow.com try:
http://ipinfodb.com/ip_query.php?timezone=false&ip=69.59.196.211
This will return an XML file containing latitude and longitude, that looks like:
69.59.196.211
OK
US
United States
41
Oregon
Corvallis
97333
44.4698
-123.343
Some VB.NET sample code is available at http://forum.ipinfodb.com/viewtopic.php?f=7&t=269