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Tutorial 4: Page 3: Invoking screen-scraper from VB.NET

Invoking screen-scraper from VB.NET

Before we dig into the code take a minute to review our Invoking screen-scraper via .NET documentation page. The VB file we'll be referring to can be downloaded here.

In order to invoke screen-scraper from VB.NET, screen-scraper needs to be running in server mode. If you'd like a refresher on how to start up screen-scraper in server mode go ahead and follow that link, then come back here.

Okay, let's try it out before we dive into the code. Start screen-scraper running as a server. From your .NET environment compile and execute the "shopping.vb" file.

If that didn't go quite as you expected here are some things to check:

  • Make sure screen-scraper is running as a server, and that nothing is blocking its ports (such as a firewall running on your machine).
  • If you're running screen-scraper on a different machine than the one your VB class resides on, make sure that screen-scraper is allowing connections from the VB machine. In the screen-scraper workbench click on the wrench icon, then on the "Servers" button, and check the "Hosts to allow to connect" includes the IP address (or perhaps just the first part of the IP address) of the VB machine.
  • Check screen-scraper's "log" folder for a "Shopping Site" log file. If you find one it means that screen-scraper is at least receiving the request. Open the log file in a text editor to see if you find any error messages.
  • If you still can't seem to get it to work feel free to drop us a support request.

Assuming that test worked, take a closer look over the "shopping.vb" class. The file is pretty heavily commented, so hopefully it makes sense what's going on. If not, try reviewing our .NET documentation, posting to our forum, or sending us a support request.

When you invoke screen-scraper as a server it creates log files corresponding to your scraping session in its "log" folder. Take a look in that folder for your "Shopping Site" log file and take a look through it. It should look similar to what you see when you run scraping sessions in the workbench.