I have a form module that needs to post values to an external payment gateway url. I stress that the data has to be sent using the HTTP POST method, not GET, and the user needs to be redirected at the same time so that they are then able to enter payment details. This POST and Redirect scenario is not well supported in ASP.NET, but I have found a workaround solution that involves rendering a HTML form back to the client browser with a javascript function that automatically submits it when the page loads.

However, whatever I have tried, I haven't been able to render the form by itself. It is always accompanied by a posted back version of the form page. What's worse is that the form doesn't autosubmit as I want it to, possibly because of interference from the other content on the page. Initially I tried using the Response.Clear and Response.End methods to clear the output buffer before rendering the form, then I even tried redirecting to another .aspx page that simply renders and posts the form. But even in that case, the form is rendered along with the form page itself.

The data should be posted when the user clicks on a Submit button in the form, a postback event which occurs late in the ASP.NET page lifecycle. That made me think that perhaps the page was already partially rendered when the Response.Clear was executed. However the form is actually rendered BEFORE the rest of the content, and so I am at a loss to understand how the page has been rendered in the way it has.

Could DNN's caching system be causing this effect?

Has anyone got a post and redirect of this sort working?

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Paul Taylor

DotNetNuke, ASP.NET and SQL Server Development