Intercept POST data C# webbrowser winform

Question

0.00/5 (No votes)

See more:

I am trying to scrape a web page. Using C# and WinForms. I can load the page into a WebBrowser, invoke the post method for a form, and get the results. I'd like to then change the date and resubmit the form. Unfortunately the control for picking the date is a read only control driven by a lot of ajax code (axd files) that aren't easily accessible.

I thought it would be better to try to intercept the POST data before it goes to the server and change the date string.

I can't seem to find a way to get the post data before it is sent to the server. Is there some way to grab it, modify it, and then send it on it's way?

What I have tried:

public void CompletedHander(object sender,
      WebBrowserDocumentCompletedEventArgs e)
{
      WebBrowser wb = ((WebBrowser)sender);

      HtmlElement button = wb.Document.GetElementById("ctl00$WebSplitter1$tmpl1$ContentPlaceHolder1$HeaderBTN1$btnRetrieve");
      if (button != null)
      {
           _pushed = true;
           button.InvokeMember("click");
      }
}

Posted 19-May-17 8:20am

mjackson11

Updated 24-May-17 6:46am

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

mjackson11 · Answer 1 · 2017-05-24T06:46:00

Turned out there was a control I could use java to invoke which created the correct viewstate and post data.

public void CompletedHander(object sender,
      WebBrowserDocumentCompletedEventArgs e)
{
    HtmlElement webDatePicker = wb.Document.GetElementById("ctl00_WebSplitter1_tmpl1_ContentPlaceHolder1_dtePickerBegin");

    string szJava = string.Empty;
    szJava = "a = $find(\"ctl00_WebSplitter1_tmpl1_ContentPlaceHolder1_dtePickerBegin\"); a.set_text(\"5/20/2017\");";
    object a = wb.Document.InvokeScript("eval", new object[] { szJava });
    if (webDatePicker != null)
        webDatePicker.InvokeMember("submit");

    HtmlElement button = wb.Document.GetElementById("ctl00$WebSplitter1$tmpl1$ContentPlaceHolder1$HeaderBTN1$btnRetrieve");
    if (button != null)
    {
         button.InvokeMember("click");
    }
}