How to post data and redirect to an external page?

Question

I am having trouble with posting data and redirecting to an external URL. The external URL is an online payment gateway that only accepts submitted form using POST method.

A simple html form like below will work without any issues

<html>
<body>
<form action="externalpage.url" method="post">
<input type="hidden" name="name1" value="1234">
<input type="hidden" name="name2" value="abcd">
<input type="submit" value="Submit Form">
</form>
</body>
</html>

But in my scenario, when the user clicks the button on my aspx page, I need to do some server side processing first, e.g. create a NameValueCollection object, before redirecting her to the payment gateway.

I have tried to use the example from this link: http://www.codeproject.com/Articles/37539/Redirect-and-POST-in-ASP-NET, but the page doesn't redirect to the external URL for some reason. The following line of code doesn't seem to do anything.

page.Controls.Add(new LiteralControl(strForm));

online payment! is it https url? http://www.terminally-incoherent.com/blog/2008/05/05/send-a-https-post-request-with-c/ — Damith, Sep 15 '13 at 09:55

score 1 · Accepted Answer · answered Sep 15 '13 at 14:39

I think I figured out how to resolve this issue. Here is what I have done.

Create an intermediate page, e.g. DoPost.aspx.

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Post Form</title>
    <script>
        function PostData() {
            document.getElementById("form1").submit();
        }
    </script>
</head>
<body onload="PostData()">
    <form id="form1" runat="server">
    <div>
        <asp:Literal ID="ltrPostData" runat="server"></asp:Literal>
    </div>
    </form>
</body>
</html>

Then in the code behind,

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        var url = "external.url";
        form1.Action = url;
        ltrPostData.Text = "Create <input type='hidden' name='data name' value='data value' /> html controls from Request.QueryString() and assign the string value to the Literal control's Text property.";
    }
}

On Submit.aspx, where the button click event happens,

//assume that the NameValueCollection object has already been created and populated  
var redirectUrl = string.Format("{0}?{1}", "DoPost.aspx", BuildQueryString(data));
Response.Redirect(redirectUrl, true);

public static string BuildQueryString(NameValueCollection data)
{
    // create query string with all values
    return string.Join("&", data.AllKeys.Select(key => string.Format("{0}={1}", HttpUtility.UrlEncode(key), HttpUtility.UrlEncode(data[key]))));
}

So effectively, we could still use Response.Redirect() to pass the data to the external link although we will need to go through a second page. In short, Submit.aspx [GET] => DoPost.aspx [Post] => The Gateway

score 0 · Answer 2 · edited May 23 '17 at 12:19

0

You need to look at HttpWebRequest.

Here's another question that pretty thoroughly explains what you need to do for your problem.

Post form data using HttpWebRequest

edited May 23 '17 at 12:19

Community

1
1

answered Sep 15 '13 at 10:37

Michael

507
5
20

score 0 · Answer 3 · answered Apr 15 '14 at 08:15

0

Here is my solution for you, a simple and elegant solution

Redirect and Post in ASP.NET by Samer Abu Rabie

answered Apr 15 '14 at 08:15

Samer Aburabie

248
2
8

score -1 · Answer 4 · answered Sep 15 '13 at 09:41

-1

Try using

Response.Redirect("http://www.microsoft.com");

Response redirect msdn

answered Sep 15 '13 at 09:41

Anobik

4,841
2
17
32

1

Since Response.Redirect uses GET, any submitted data using GET will be rejected by the gateway unfortunately :( – woodykiddy Sep 15 '13 at 09:47

How to post data and redirect to an external page?

4 Answers4