Generate WSDL FROM salesforce system and How to convert WSDL file to class file

LOGIN to Salesforce

On right side 

Click on setup

then Search for API in search tab

Click on Generate enterprise wsdl 

Then its generates the wsdl and copy and paste it notepad

Save As "SDFC.wsdl"

How to convert WSDL file to class file

1. In Solution Explorer right click on your project and go to "Add Service Reference..."
2. Press "Advanced..." at the bottom of the window.
3. Press "Add Web Reference..." at the bottom of the window.
4. In the URL field enter the path to the file eg. C:\Documents and Settings\username\Desktop\filename
5. Press Go arrow. Service description should display.
6. Enter the reference name you wish.
7. Press "Add reference".
8. Watch Visual Studio do its magic and making your life easy.
9. Take a break.