I need to transfer a user from an ASP.NET application to an ASP application at one point during a holiday booking process. The search for locations and options etc happens in the ASP.NET application, but to take payment and finalize the booking I need to transfer the user over to an existing ASP application. At the point when they need to be transferred, there is a large amount of object data stored in the viewstate which represents the options they have chosen.

I have thought of 3 possibilities to acheive this.

1. simply post the viewstate and extract the data out on the ASP side. This is a very neat solution on the ASP.NET side, but unfortunately creates a lot of complexity on the ASP side. I have not had any luck in attempting to decode the viewstate in ASP.

2. Have a hidden field on the ASP.net form which contains an XML representation of the data, which can be posted to the ASP app and easily interpreted there. My concern with this approach is that all that data is already in the page's viewstate and so adding it all to another field will make the page even bigger and therefore slower to load. (But most people use broadband these days, so maybe its not such a big deal any more).

3. post back the ASP.NET web form, and in the event handler simply redirect to the url of the ASP app with all the data encrypted into the querystring. This would be a neat a simple solution, but querystring can be tamperred with easily and also has a size limit.

For options 2 and 3, i would need some way to encode the data that can easily be decoded at the other end. At this point, the data is not sensitive so i don't need a high degree of encryption, just enough to obscure the data from the user.

(I am programming both sides of the system, so am not restriced in the solution i choose).

Has anyone out there successfully done something like this? I will welcome any helpful suggestions or advice. Also let me know if theres any other forums that might be able to help me.

Cheers!

Hi,

In option 3 if the form method is 'POST' all the form data is hidden from the user, it only appears in the Querystring if your form method is 'GET'.

just to clarify, what i meant in option 3 was that the ASP.NET page would post back to itself, and then use

response.redirect "path/filename.asp?data=" & strEncodedData

to transfer the data to the ASP application.

In option 2, it would either submit the form directly to the ASP application (using the post method), or it would post back to itself and use 'server.transfer' to post the form data to the ASP application.

The data would be a big chunk of XML which is created by serialising the object data from the viewstate. i would want to encode it somehow so that if the user views the source of the page they would not see the XML data itself.