Question: I am relatively new to T4 templates. I am working in visual studio 2012 and using the tangible T4 editor. I have my text templates in one project and I want to read a class in another project and do some processing and write the generated code to a third project. I want to pass in the class file path to my template For example "C:/Code/Project2/ClassFooBar.cs" and the template will read the class from the given location and do some processing with the class properties and write the generated code to project3. I want to pass in the file path since my project has a number of class files and there is not a pattern that I can specify in the template.

My solution structure is:

```
SolutionFoo:
 - Project1
    -TextTemplate.tt   

 - Project2
   - ClassFooBar.cs

 - Project3
    -GeneratedCode.cs

```

anyone can guide me with a clean way of passing in the class path and a way to writing the generated code to Project3?

Answer: 
In the form action, you are directing to **<https://www.paypal.com/cgi-bin/webscr>**

But In the IPN code your

```
$ch = curl_init('https://www.sandbox.paypal.com/cgi-bin/webscr');

```

So one points to the sandbox, but not the other. That should be the problem.
The problem is in your IPN handler, not in this code. It should be obvious that this code must work, otherwise no IPN would have happened at all. You need to post the *relevant* code. Probably you haven't built the validation callback URL correctly, or you aren't sending it to the right URL (sandbox or live).