Find a lot online. Success, share with you my experience. (I didn't encounter so many problems)
I used vs2010 Professional Edition.
The computer should start function, otherwise it will make mistakes.
Look patiently.
Next, use vs. to
first create a web project. There is no empty web application, because the subsequent lack of configuration errors can be avoided.
After adding new items, after adding 
, the code will automatically generate a hello world, and then right-click on your project name, as follows
Click on the release, select the file system, select a directory, the directory to remember.
Next open ISS,
click on the default document, is to open this address, the default interface,
add our new asmx file,
now you can click to browse the website, it can be displayed normally.
We next want to call the webService that we just created.
Still open VS and create 
this interface, indicating that it is ok .
The output is as follows
