Develop Reference

WebBrowser.Document is null on return from thread, not updating in new thread

public static User registerUser()
{
Uri test = new Uri("https://www.example.com/signup");
HtmlDocument testdoc = runBrowserThread(test);
string tosend = "test";
User user = new User();
user.apikey = tosend;
return user;
}
public static HtmlDocument runBrowserThread(Uri url)
{
HtmlDocument value = null;
var th = new Thread(() =>
{
var br = new WebBrowser();
br.DocumentCompleted += browser_DocumentCompleted;
br.Navigate(url);
value = br.Document;
Application.Run();
});
th.SetApartmentState(ApartmentState.STA);
th.Start();
th.Join(8000);
return value;
}
static void browser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
var br = sender as WebBrowser;
if (br.Url == e.Url)
{
Console.WriteLine("Natigated to {0}", e.Url);
Console.WriteLine(br.Document.Body.InnerHtml);
System.Console.ReadLine();
Application.ExitThread(); // Stops the thread
}
}
I am trying to scan this page, and while it does get the HTML it does not pass it back in to the function call, but instead sends back null (I presume that is post processing).
How can I make it so that the new thread passes back its result?

There are several problems with your approach.
You're not waiting till the webpage is navigated, I mean till Navigated event. So document could be null till then.
You're quitting after 8 seconds, if page takes more than 8 seconds to load you won't get the document.
If document isn't properly loaded, you're leaving the thread alive.
I guess WebBrowser control will not work as expected unless you add it into a form and show it(it needs to be visible in screen).
Etc..
Don't mix up things. Your goal can't be to use WebBrowser. If you need to just download the string from webpage, use HttpClient.GetStringAsync.
Once you get the page as string format, If you want to manipulate the html, use HtmlAgilityPack.

Moved over to using WaitN instead of the default browser model. A bit buggy but now works like it should do.
using (var browser = new FireFox("https://www.example.com/signup"))
{
browser.GoTo("https://example.com/signup");
browser.WaitForComplete();
}

How to make WebBrowser wait till it loads fully?

I have a C# form with a web browser control on it.
I am trying to visit different websites in a loop.
However, I can not control URL address to load into my form web browser element.
This is the function I am using for navigating through URL addresses:
public String WebNavigateBrowser(String urlString, WebBrowser wb)
{
string data = "";
wb.Navigate(urlString);
while (wb.ReadyState != WebBrowserReadyState.Complete)
{
Application.DoEvents();
}
data = wb.DocumentText;
return data;
}
How can I make my loop wait until it fully loads?
My loop is something like this:
foreach (string urlAddresses in urls)
{
WebNavigateBrowser(urlAddresses, webBrowser1);
// I need to add a code to make webbrowser in Form to wait till it loads
}

Add This to your code:
webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
Fill in this function
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) {
//This line is so you only do the event once
if (e.Url != webBrowser1.Url)
return;
//do you actual code
}

After some time of anger of the crappy IE functionality I've came across making something which is the most accurate way to judge page loaded complete.
Never use the WebBrowserDocumentCompletedEventHandler event
use WebBrowserProgressChangedEventHandler with some modifections seen below.
//"ie" is our web browser object
ie.ProgressChanged += new WebBrowserProgressChangedEventHandler(_ie);
private void _ie(object sender, WebBrowserProgressChangedEventArgs e)
{
int max = (int)Math.Max(e.MaximumProgress, e.CurrentProgress);
int min = (int)Math.Min(e.MaximumProgress, e.CurrentProgress);
if (min.Equals(max))
{
//Run your code here when page is actually 100% complete
}
}
Simple genius method of going about this, I found this question googling "How to sleep web browser or put to pause"

According to MSDN (contains sample source) you can use the DocumentCompleted event for that. Additional very helpful information and source that shows how to differentiate between event invocations can be found here.

what you experiencend happened to me . readyStete.complete doesnt work in some cases. here i used bool in document_completed to check state
button1_click(){
//go site1
wb.Navigate("site1.com");
//wait for documentCompleted before continue to execute any further
waitWebBrowserToComplete(wb);
// set some values in html page
wb.Document.GetElementById("input1").SetAttribute("Value", "hello");
// then click submit. (submit does navigation)
wb.Document.GetElementById("formid").InvokeMember("submit");
// then wait for doc complete
waitWebBrowserToComplete(wb);
var processedHtml = wb.Document.GetElementsByTagName("HTML")[0].OuterHtml;
var rawHtml = wb.DocumentText;
}
// helpers
//instead of checking readState . we get state from DocumentCompleted Event via bool value
bool webbrowserDocumentCompleted = false;
public static void waitWebBrowserToComplete(WebBrowser wb)
{
while (!webbrowserDocumentCompleted )
Application.DoEvents();
webbrowserDocumentCompleted = false;
}
form_load(){
wb.DocumentCompleted += (o, e) => {
webbrowserDocumentCompleted = true;
};
}

WebBrowser.Document.Body is always null

I have a WebBrowser document set to be in edit mode. I am trying to manipulate the inner text of the body element by using WebBrowser.Document.Body.InnerText, however, WebBrowser.Document.Body remains null.
Here is the code where I create the document contents:
private WebBrowser HtmlEditor = new WebBrowser();
public HtmlEditControl()
{
InitializeComponent();
HtmlEditor.DocumentText = "<html><body></body></html>";
myDoc = (IHTMLDocument2)HtmlEditor.Document.DomDocument;
myDoc.designMode = "On";
HtmlEditor.Refresh(WebBrowserRefreshOption.Completely);
myContentsChanged = false;
}
I can edit code and everything fine, but I don't understand why HtmlEditor.Document.Body remains null. I know I could always just reset the document body whenever I need to load text into the form, but I would prefer to understand why this is behaving the way it is, if nothing else then for the knowledge.
Any help on this is greatly appreciated.

You have to wait for the Web Browser's DocumentCompleted event to fire for the DomDocument.Body to not be null. I just tested this to verify. I suppose the question still remains: how are you able to edit through the underlying COM interface when the document has not completely loaded?
I checked to see if the IHTMLDocument2 pointers were the same in DocumentCompleted and the constructor. They are, which might indicate that the underlying COM object reuses a single HTML document object. It seems like any changes you make in the constructor at least have a pretty good chance of getting overwritten or throwing an exception.
For example, if I do this in the constructor, I get an error:
IHTMLDocument2 p1 = (IHTMLDocument2) HTMLEditor.Document.DomDocument;
p1.title = "Hello world!";
If I do the same in a DocumentCompleted handler, it works fine.
Hope this helps. Thanks.

Use DocumentCompleted event first, it occurs when the WebBrowser control finishes loading a document:
public HtmlEditControl()
{
InitializeComponent();
HtmlEditor.DocumentText = "<html><body></body></html>";
HtmlEditor.DocumentCompleted += HtmlEditorDocumentCompleted;
}
void HtmlEditorDocumentCompleted(object sender,
WebBrowserDocumentCompletedEventArgs e)
{
myDoc = (IHTMLDocument2)((WebBrowser)sender).Document.DomDocument;
myDoc.designMode = "On";
HtmlEditor.Refresh(WebBrowserRefreshOption.Completely);
myContentsChanged = false;
}
or simple way:
public HtmlEditControl()
{
InitializeComponent();
HtmlEditor.DocumentText = "<html><body></body></html>";
HtmlEditor.DocumentCompleted += (sender, e) =>
{
myDoc = (IHTMLDocument2) HtmlEditor.Document.DomDocument;
myDoc.designMode = "On";
HtmlEditor.Refresh(WebBrowserRefreshOption.Completely);
myContentsChanged = false;
};
}

You need to let the WebBrowser control to work alone a bit to give it some time to set the Document.Body property.
I do that by calling Application.DoEvents();.
For instance in your code:
private WebBrowser HtmlEditor = new WebBrowser();
public HtmlEditControl()
{
InitializeComponent();
HtmlEditor.DocumentText = "<html><body></body></html>";
// Let's leave the WebBrowser control working alone.
while (HtmlEditor.Document.Body == null)
{
Application.DoEvents();
}
myDoc = (IHTMLDocument2)HtmlEditor.Document.DomDocument;
myDoc.designMode = "On";
HtmlEditor.Refresh(WebBrowserRefreshOption.Completely);
myContentsChanged = false;
}

if (HtmlEditor.Document.Body == null)
{
HtmlEditor.Document.OpenNew(false).Write(#"<html><body><div id=""editable""></div></body></html>");
}
HtmlEditor.Document.Body.SetAttribute("contentEditable", "true");

AlertControl doesn't show

I have a strange problem with devexpress AlertControl. I create an alertu using this code
AlertInfo alertInfo = new AlertInfo(caption, text);
AlertControl control = new AlertControl();
control.FormLocation = AlertFormLocation.BottomRight;
control.Show(null,alertInfo);
this code is placed in backgroundWorker_DoWork function and it is supposed to display alerts from time to time. The problem is that alerts are not shown. I can see that show method is invoked however alerts are not shown.
Acording to documentation is I pass null as a parametr of Show function , notification should be shown on main monitor.
What can I do to make it work ?

Considering you're using a worker, I guess it's a thread problem. Try wrapping your code inside an Action object:
Action action = () =>
{
AlertControl control = new AlertControl();
control.FormLocation = AlertFormLocation.BottomRight;
control.Show(this, alertInfo); // "this" being a Form
};
this.Invoke(action);
I use a similar code inside a form with good results and once did a similar code using an AlertControl too.

Your AlertControl need a Parent Control.
AlertControl control = new AlertControl();
control.FormLocation = AlertFormLocation.BottomRight;
control.Show(MyForm,alertInfo); //replace null with a Form/Control instance
You call the Show method with a null paramater - where you should have use an instance of a Form/Control

Don't know anything about the devexpress controls, but maybe you have to show the alert from the main thread via invoke methode?

using DevExpress.XtraBars.Alerter;
// Create a regular custom button.
AlertButton btn1 = new AlertButton(Image.FromFile(#"c:\folder-16x16.png"));
btn1.Hint = "Open file";
btn1.Name = "buttonOpen";
// Create a check custom button.
AlertButton btn2 = new AlertButton(Image.FromFile(#"c:\clock-16x16.png"));
btn2.Style = AlertButtonStyle.CheckButton;
btn2.Down = true;
btn2.Hint = "Alert On";
btn2.Name = "buttonAlert";
// Add buttons to the AlertControl and subscribe to the events to process button clicks
alertControl1.Buttons.Add(btn1);
alertControl1.Buttons.Add(btn2);
alertControl1.ButtonClick += new AlertButtonClickEventHandler(alertControl1_ButtonClick);
alertControl1.ButtonDownChanged +=
new AlertButtonDownChangedEventHandler(alertControl1_ButtonDownChanged);
// Show a sample alert window.
AlertInfo info = new AlertInfo("New Window", "Text");
alertControl1.Show(this, info);
void alertControl1_ButtonDownChanged(object sender,
AlertButtonDownChangedEventArgs e) {
if (e.ButtonName == "buttonOpen") {
//...
}
}
void alertControl1_ButtonClick(object sender, AlertButtonClickEventArgs e) {
if (e.ButtonName == "buttonAlert") {
//...
}
}
ref:https://documentation.devexpress.com/#WindowsForms/clsDevExpressXtraBarsAlerterAlertControltopic

IE Instance, DocumentCompleted Executing Too Soon

I create an instance of IE outside my program, which the program finds and attaches to correctly. I set up my event handler and tell the program to advance to the login screen. The DocumentCompleted handle is supposed to fire when the web page is completely loaded, but mine seems to be firing before the new page has appeared.. The handle only fires once (meaning there is only one frame?).
This code executes fine if I modify it to work straight from the login page also.. Am I doing something wrong? Thanks for any assistance :)
Process.Start(#"IESpecial.exe");
SHDocVw.ShellWindows allBrowsers = new SHDocVw.ShellWindows();
while (true)
{
foreach (SHDocVw.WebBrowser ie in allBrowsers)
{
if (ie.LocationURL == "http://website/home.asp")
{
loggingIn = true;
webBrowser = ie;
webBrowser.DocumentComplete += new SHDocVw.DWebBrowserEvents2_DocumentCompleteEventHandler(webBrowser1_DocumentCompleted);
webBrowser.Navigate("http://website/logon.asp");
return;
}
}
Thread.Sleep(10);
}
}
private void webBrowser1_DocumentCompleted(object pDisp, ref object URL)
{
//we are attempting to log in
if (loggingIn)
{
mshtml.HTMLDocumentClass doc = (mshtml.HTMLDocumentClass)webBrowser.Document;
mshtml.HTMLWindow2 window = (mshtml.HTMLWindow2)doc.IHTMLDocument2_parentWindow;
doc.getElementById("Username").setAttribute("value", "MLAPAGLIA");
doc.getElementById("Password").setAttribute("value", "PASSWORD");
window.execScript("SubmitAction()", "javascript");
loggingIn = false;
return;
}