Question

Here’s my scenario:

I have one page that collects certain data from the user.
I want to have one button that the user can click, and I want this button to do two things.

a) Log data to my database.
b) Redirect the user to Paypal to make a payment.

My current thought is to create an intermediate “handler” page which will do a) and then redirect the brower to b).

The question is: How do I actually do b)? (Is it some combination of JS and ASP?)
My hope is to have it behave exactly as if the data-collecting page had performed the POST to PayPal directly, but if that is not possible, I welcome other suggestions to implement my scenario.

The back end technology I am using is ASP.NET.

Answer 1

After some more specific Googling and testing, the solution that worked out for me was to use the code linked here:

http://www.codeproject.com/KB/aspnet/ASP_NETRedirectAndPost.aspx

As you can see … we prepare the POST form which is an HTML form that holds the hidden fields of your POSTed data and a script tag which holds the submit operation of the form .. which will be executed immediately upon the postback.

private static String PreparePOSTForm(string url, NameValueCollection data)
{
    //Set a name for the form
    string formID = "PostForm";
    //Build the form using the specified data to be posted.
    StringBuilder f = new StringBuilder();
    f.Append("<form id=\"" + formID + "\" name=\"" + 
                   formID + "\" action=\"" + url + 
                   "\" method=\"POST\">");

    foreach (string key in data)
    {
        f.Append("<input type=\"hidden\" name=\"" + key + 
                       "\" value=\"" + data[key] + "\">");
    }

    f.Append("</form>");
    //Build the JavaScript which will do the Posting operation.
    StringBuilder s = new StringBuilder();
    s.Append("<script language="'javascript'">");
    s.Append("var v" + formID + " = document." + 
                     formID + ";");
    s.Append("v" + formID + ".submit();");
    s.Append("</script>");
    //Return the form and the script concatenated.
    //(The order is important, Form then JavaScript)
    return f.ToString() + s.ToString();
}