Down & Dirty .NET PayPal Buttons?

CAN IT BE?
Yes, my friends it is possible… I think.  Bottom line is, you can design buttons all day long in PayPal and there are various ways to get them working.  However, since I am far too dense for GhostForms, I found my own little path.

GO GET YOUR BUTTONS
Now, I am not going to drill into PayPal buttons… their website will generate both hosted and non-hosted buttons for you.  I am opting for non-hosted because then I can actually have my website generate the buttons based on info in my website/database. Handy.

I HAVE BUTTONS, NOW WHAT?
Once you have your buttons, you can do many things.  What I wanted was to have CONTROL! (Sound FX: Maniacal laughter), so I wanted to generate the parameters for my buttons. But there are a couple caveats:
1) I didn’t want the guts of my button in the HTML of the web page for people to examine and hack.
2) I didn’t want the guts of my button on a URL for folks to hack! Hacker: “What’s that price? I think I will just set that to price=-50.00 so Ted owes ME! Hahaha!”

This means, my users will click a button, and my server code will generate an HttpRequest that goes to PayPal, passing it a POST so that PayPal can come back with their shopping page. It goes like this: 

SOURCES
http://stackoverflow.com/questions/698029/invoking-a-post-to-an-external-site-with-c-httpwebrequest
http://www.csharp-station.com/HowTo/HttpWebFetch.aspx

CODE:
//This goes wherever you need it… button click, page load, etc.
//You need System.IO, System.NET, System.Text

//make a button (just for this demo – see PayPal documents)
//NOTE: ampersands used to make a psuedo URL…
            StringBuilder ParamsAsString = new StringBuilder();
            string Url = “https://www.paypal.com/cgi-bin/webscr“;
            ParamsAsString.Append(“cmd=_xclick-subscriptions”);
            ParamsAsString.Append(“&business=your@paypal.email“);
            ParamsAsString.Append(“&lc=US”);
            ParamsAsString.Append(“&item_name=productname”);
            ParamsAsString.Append(“&item_number=productid”);
            ParamsAsString.Append(“&no_note=1″);
            ParamsAsString.Append(“&no_shipping=1″);
            ParamsAsString.Append(“&a3=25.95″);
            ParamsAsString.Append(“&currency_code=USD”);
            ParamsAsString.Append(“&src=1″);
            ParamsAsString.Append(“&p3=1″);
            ParamsAsString.Append(“&t3=M”);
            ParamsAsString.Append(“&sra=1″);
            ParamsAsString.Append(“&bn=PP-SubscriptionsBF:btn_subscribeCC_LG.gif:NonHosted”);
//convert params to a byte array
            byte[] paramStream = Encoding.ASCII.GetBytes(ParamsAsString.ToString());

//create a request
            HttpWebRequest ppr = (HttpWebRequest)WebRequest.Create(Url);
            ppr.Method = “POST”;
            ppr.ContentType = “application/x-www-form-urlencoded”;
            ppr.UserAgent = “Mozilla/5.0 (Windows; U; Windows NT 6.0; sv-SE; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2″;
            ppr.ContentLength = paramStream.Length;

//Get request stream and put our parameters there!
            using (var stream = ppr.GetRequestStream())
            {
                stream.Write(paramStream, 0, paramStream.Length);
            }

//Send this to PayPal and get response
            var response = ppr.GetResponse();
            string result;
            using (var sr = new StreamReader(response.GetResponseStream()))
            {
                result = sr.ReadToEnd();
            }

//Write this to the user’s browser
            Response.RedirectLocation = “https://www.paypal.com/cgi-bin/webscr“;
            Response.Write(result);
//Be Done! Don’t process the rest of the page…
            Response.Flush();
            Response.End();

NOTES:
I set the RedirectLocation because I feel guilty.  Also, the Flush() and End() stop the rest of the page from processing.  Since you just wrote a complete HTML page from PayPal, continuing to write more will just be weird!!

Now, you might also notice is that the URL on the web page is still YOUR url, but all the buttons, content and everything else, having been put together on the remote website’s server (PayPal in this case) are all set up to point to the correct place…so you should be good to go.

Happy Coding!

Package Load Failure Microsoft.VisualStudio.Xaml

BACKGROUND
Well, if you are like me, you downloaded the Express version of Visual Studio 2008 because you were too impatient to wait the 3 days for the DVD to arrive in the mail.  Then it arrived and took 10 years to install, and after firing up  Visual Studio 2008, you get a “Package Load Failure” siting Microsoft.VisualStudio.Xaml.  Afterwords, you notice there is no XAML intellisense.  After a brief bout of insanity – running around screaming, chewing on the cat’s leg, sending the children to bed at 3pm – you then calmly search the web.

FIX
I removed the express editions. No Go.

I ran the repairs suggested here. No go (and, my default key in my registry was not blank, so I was just trying it because I could).

I ran the devenv.exe /setup suggested here (found it buried in an article):
“If you are still hitting this, I just found a fix.  Using cmd, navigate to the Visual Studio 2008 (9.0) folder in the Program Files folder.  cd to Common7\IDE.  Type, “devenv.exe /setup”

You can open taskmgr to monitor the devenv process.  When it’s done, just reopen visual studio and xml should start rendering.  At least it worked for me.  Good luck.”

I deleted the toolbar temp files (and I can’t find the link – sorry) which are located in C:\Documents and Settings under your username, then look under Local Settings\Application Data\Microsoft\VisualStudio\9.0 (or something similar) and delete the .tbd files there. No go

What worked for me was to download and re-run Visual Studio 2008 Service Pack 1

Now it could JUST be SP1, or maybe a combination of steps – so I would recommend running the last three.  Of course if this obliterates your system, then I am not liable…all this stuff is DO AT YOUR OWN RISK!

Enjoy the XAML Goodness (or so I hope)!