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WPF WebBrowser scroll on reload

I have a System.Windows.Controls.WebBrowser. It has some html that is coming from another document that the user is editing. When the html changes, what I want to do is update the WebBrowser's html, then scroll the WebBrowser back to wherever it was. I am successfully cacheing the scroll offset (see How to retrieve the scrollbar position of the webbrowser control in .NET). But I can't get a callback when the load is complete. Here is what I have tried:
// constructor
public HTMLReferenceEditor()
{
InitializeComponent();
WebBrowser browser = this.EditorBrowser;
browser.LoadCompleted += Browser_LoadCompleted;
//browser.Loaded += Browser_Loaded; // commented out as it doesn't fire when the html changes . . .
}
private void Browser_LoadCompleted(object sender, System.Windows.Navigation.NavigationEventArgs e)
{
CommonDebug.LogLine("LoadCompleted");
this.ScrollWebBrowser();
}
private void ScrollWebBrowser()
{
WebBrowser browser = this.EditorBrowser;
ReferenceHierarchicalViewModel rhvm = this.GetReferenceHierarchichalViewModel();
int? y = rhvm.LastKnownScrollTop; // this is the cached offset.
browser?.ScrollToY(y);
}
The LoadCompleted callbacks are firing all right. But the scrolling is not happening. I suspect the callbacks are coming too soon. But it is also possible that my scroll method is wrong:
public static void ScrollToY(this WebBrowser browser, int? yQ)
{
if (yQ.HasValue)
{
object doc = browser?.Document;
HTMLDocument castDoc = doc as HTMLDocument;
IHTMLWindow2 window = castDoc?.parentWindow;
int y = yQ.Value;
window?.scrollTo(0, y);
CommonDebug.LogLine("scrolling", window, y);
// above is custom log method; prints out something like "scrolling HTMLWindow2Class3 54", which
// at least proves that nothing is null.
}
}
How can I get the browser to scroll? Incidentally, I don't see some of the callback methods others have mentioned, e.g. DocumentCompleted mentioned here does not exist for me. Detect WebBrowser complete page loading. In other words, for some reason I don't understand, my WebBrowser is different from theirs. For me, the methods don't exist.

How to loop HTML printing when using a list?

I have a list, which contains paths to html files on my PC. I would like to loop through this list and print them all, in the same order they are in the list.
I tried to loop the code that i have found on msdn.microsoft.com for printing an HTML file.
List<string> AllHTMLsToPrint = new List<string>();
//things added to AllHTMLsToPrint list
foreach (string strHTMLToPrint in AllHTMLsToPrint)
{
PrintHelpPage(strHTMLToPrint);
}
private void PrintHelpPage(string strHTMLToPrint)
{
// Create a WebBrowser instance.
WebBrowser webBrowserForPrinting = new WebBrowser();
// Add an event handler that prints the document after it loads.
webBrowserForPrinting.DocumentCompleted +=
new WebBrowserDocumentCompletedEventHandler(PrintDocument);
// Set the Url property to load the document.
webBrowserForPrinting.Url = new Uri(strHTMLToPrint);
Thread.Sleep(100);
}
private void PrintDocument(object sender, WebBrowserDocumentCompletedEventArgs e)
{
// Print the document now that it is fully loaded.
((WebBrowser)sender).Print();
// Dispose the WebBrowser now that the task is complete.
((WebBrowser)sender).Dispose();
}

You have a design problem here. You walk your list of html pages to print. Then you open the page in a browser. When the page is loaded you print it.
BUT...
Loading the page may take longer than 100ms. This is the time after which the browser loads the next page. You should change your code so that the next page will load after the current one has been printed. You may not want to use a loop in this case but an index which you may want to increment after printing.
Should look similar to this (not tested):
List<string> AllHTMLsToPrint = new List<string>();
private int index = 0;
PrintHelpPage(AllHTMLsToPrint[index]);
private void PrintHelpPage(string strHTMLToPrint)
{
// Create a WebBrowser instance.
WebBrowser webBrowserForPrinting = new WebBrowser();
// Add an event handler that prints the document after it loads.
webBrowserForPrinting.DocumentCompleted +=
new WebBrowserDocumentCompletedEventHandler(PrintDocument);
// Set the Url property to load the document.
webBrowserForPrinting.Url = new Uri(strHTMLToPrint);
}
private void PrintDocument(object sender, WebBrowserDocumentCompletedEventArgs e)
{
// Print the document now that it is fully loaded.
((WebBrowser)sender).Print();
if (index < AllHTMLsToPrint.Count -1)
PrintHelpPage(AllHTMLsToPrint[++index]);
}

You've stated that you have a bunch of local html files.
The loading of local html files may not work by setting the URI.
You could try setting the DocumentStream instead. strHTMLToPrint must then contain the full/relative path to your local html file.
webBrowserForPrinting.DocumentStream = File.OpenRead(strHTMLToPrint);

Not sure what the exact issue is, but I would put this into a background worker so you don't hold up the main thread. I'd also move the loop into the document loaded system, that way as soon as it has loaded and printed it will move onto the next.
That said you haven't said what your code isn't doing.
public partial class Form1 : Form
{
internal List<string> AllHTMLsToPrint = new List<string>();
public Form1()
{
InitializeComponent();
}
public void StartPrinting()
{
//things added to AllHTMLsToPrint list, please note you may need to add file:/// to the URI list if it is a local file, unless it is compact framework
// start printing the first item
BackgroundWorker bgw = new BackgroundWorker();
bgw.DoWork += bgw_DoWork;
bgw.RunWorkerAsync();
/*foreach (string strHTMLToPrint in AllHTMLsToPrint)
{
PrintHelpPage(strHTMLToPrint);
}*/
}
void bgw_DoWork(object sender, DoWorkEventArgs e)
{
PrintHelpPage(AllHTMLsToPrint[0], (BackgroundWorker)sender);
}
private void PrintHelpPage(string strHTMLToPrint, BackgroundWorker bgw)
{
// Create a WebBrowser instance.
WebBrowser webBrowserForPrinting = new WebBrowser();
// Add an event handler that prints the document after it loads.
webBrowserForPrinting.DocumentCompleted += (s, ev) => {
webBrowserForPrinting.Print();
webBrowserForPrinting.Dispose();
// you can add progress reporting here
// remove the first element and see if we have to do it all again
AllHTMLsToPrint.RemoveAt(0);
if (AllHTMLsToPrint.Count > 0)
PrintHelpPage(AllHTMLsToPrint[0], bgw);
};
// Set the Url property to load the document.
webBrowserForPrinting.Url = new Uri(strHTMLToPrint);
}
}

Cannot get rendered html via WebBrowser

I want to get html code from website. In Browser I usually can just click on ‘View Page Source’ in context menu or something similar. But how can I automatized it? I’ve tried it with WebBrowser class but sometimes it doesn’t work. I am not web developer so I don’t really know if my approach at least make sense. I think main problem is that I sometimes get html where not all code was executed. Hence it is uncompleted. I have problem with e.g. this site: http://www.sreality.cz/en/search/for-sale/praha
My code (I’ve tried to make it small but runnable on its own):
using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WebBrowserForm
{
internal static class Program
{
[STAThread]
private static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
for (int i = 0; i < 10; i++)
{
Form1 f = new Form1();
f.ShowDialog();
}
// Now I can check Form1.List and see that some html is final and some is not
}
}
public class Form1 : Form
{
public static List<string> List = new List<string>();
private const string Url = "http://www.sreality.cz/en/search/for-sale/praha";
private System.Windows.Forms.WebBrowser webBrowser1;
public Form1()
{
this.webBrowser1 = new System.Windows.Forms.WebBrowser();
this.SuspendLayout();
this.webBrowser1.Dock = System.Windows.Forms.DockStyle.Fill;
this.webBrowser1.Name = "webBrowser1";
this.webBrowser1.TabIndex = 0;
this.ResumeLayout(false);
Load += new EventHandler(Form1_Load);
this.webBrowser1.ObjectForScripting = new MyScript();
}
private void Form1_Load(object sender, EventArgs e)
{
webBrowser1.Navigate(Url);
webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
}
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
if (webBrowser1.ReadyState == WebBrowserReadyState.Complete)
{
// Final html for 99% of web pages, but unfortunately not for all
string tst = webBrowser1.Document.GetElementsByTagName("HTML")[0].OuterHtml;
webBrowser1.DocumentCompleted -= new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
Application.DoEvents();
webBrowser1.Navigate("javascript: window.external.CallServerSideCode();");
Application.DoEvents();
}
}
[ComVisible(true)]
public class MyScript
{
public void CallServerSideCode()
{
HtmlDocument doc = ((Form1)Application.OpenForms[0]).webBrowser1.Document;
string renderedHtml = doc.GetElementsByTagName("HTML")[0].OuterHtml;
// here I sometimes get full html but sometimes the same as in webBrowser1_DocumentCompleted method
List.Add(renderedHtml);
((Form1)Application.OpenForms[0]).Close();
}
}
}
}
I would expect that in ‘webBrowser1_DocumentCompleted’ method I could get final html. It usually works, but with this site it doesn’t. So I’ve tried get html in my own code which should be executed in web site -> method ‘CallServerSideCode’. What is strange that sometimes I get final html (basically the same as if I do it manually via Browser) but sometimes not. I think the problem is caused because my script start before whole web site is rendered instead after. But I am not really sure since this kind of things are far from my comfort zone and I don’t really understand what I am doing. I’m just trying to apply something what I found on the internet.
So, does anyone knows what is wrong with the code? Or even more importantly how to easily get final html from the site?
Any help appreciated.

You should use WebClient class to download HTML page. No display control necessary.
You want method DownloadString

May be it will be helpful if you add calling of your external function to the end of the body and wrap it by Jquery "ondomready" function. I mean something like this:
private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
if (webBrowser1.ReadyState == WebBrowserReadyState.Complete)
{
// Final html for 99% of web pages, but unfortunately not for all
string tst = webBrowser1.Document.GetElementsByTagName("HTML")[0].OuterHtml;
webBrowser1.DocumentCompleted -= new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);
HtmlElement body = webBrowser1.Document.GetElementsByTagName("body")[0];
HtmlElement scriptEl = webBrowser1.Document.CreateElement("script");
IHTMLScriptElement element = (IHTMLScriptElement)scriptEl.DomElement;
element.text = "$(function() { window.external.CallServerSideCode(); });";
body.AppendChild(scriptEl);
}
}
[ComVisible(true)]
public class MyScript
{
public void CallServerSideCode()
{
HtmlDocument doc = ((Form1)Application.OpenForms[0]).webBrowser1.Document;
string renderedHtml = doc.GetElementsByTagName("HTML")[0].OuterHtml;
// here I sometimes get full html but sometimes the same as in webBrowser1_DocumentCompleted method
List.Add(renderedHtml);
((Form1)Application.OpenForms[0]).Close();
}
}

Frame.Navigate in LoadState

I'm having trouble trying to navigate automatically between pages in my Windows 8.1 app based on a little check. It just doesn't want to navigate to another page when doing this in LoadState, as if something isn't loaded yet, but it doesn't give an error either. When I insert a delay using (for example) await Task.Delay(2000) before doing Frame.Navigate, then my app will redirect without any problem.
protected async override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)
{
MyData oData = await getData();
if (oData != null)
{
this.Frame.Navigate(typeof(newPage), oData);
}
else
{
// do something else
}
}
Do I have to put this code in another load- or navigated-event? Or how can I make this work?

In LoadState and SaveState you should only save and restore the page state (called when suspending and reactivating the app). Do nothing else (like navigating).
Put your logic into the OnNavigatedTo method instead...

If you want to navigate from method that called when page is loads, you should place your navigation code to OnNavigatedTo(...). But do not forget to wrap your code in Dispatcher.RunAsync(...) - Frame navigation in xaml return false

I tried calling Frame.Navigate(...) from the OnNavigatedTo method but still the navigation didn't occur.
There are other answers which say use Dispatcher.RunAsync, but that feels like it's making assumptions about the threading model of Windows Phone.
Here's what I do: attach a handler to the Loaded event of the page instead, and put my "redirect" logic in there. Loaded fires after OnNavigateTo and after NavigationHelper_LoadState, but before the page has become visible.
public LaunchPadPage() {
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += this.NavigationHelper_LoadState;
this.navigationHelper.SaveState += this.NavigationHelper_SaveState;
this.Loaded += LaunchPadPage_Loaded;
this.app = (App)App.Current;
}
private void NavigationHelper_LoadState(object sender, LoadStateEventArgs e) {
// Let's show the root zone items
// NB: In case we don't have this data yet, do nothing
if (app.Hierarchy != null)
{
DefaultViewModel["Items"] = app.Hierarchy.RootItems;
}
}
private void LaunchPadPage_Loaded(object sender, RoutedEventArgs e) {
// No data? Go to the downloads page instead.
if (app.Hierarchy == null)
{
Frame.Navigate(typeof(DownloadingPage));
}
}

Webkit.Net wait for page to be fully loaded

I'm trying to make an C# windows form application, with an webbrowser.
I'm using the webkit browser: Link to the browser
The webbrowser did i put in an class file, so i can acces it through all the forms i'm going to use.
The code that's generate the webbrowser:
public static WebKit.WebKitBrowser mainBrowser = new WebKitBrowser();
I'm having this piece of code that give's some problems:
globalVars.mainBrowser.Navigate("http://www.somesite.com/");
while (globalVars.mainBrowser.IsBusy)
{
System.Threading.Thread.Sleep(500);
}
globalVars.mainBrowser.Document.GetElementById("user").TextContent = "User Name";
But it's not working. If i do an message box after the while, it shows up before it's possible to render the page...
So what is the best way to wait until the site is fully loaded?
UPDATE 1
In an standalone class file, am i making the webkit controll like this:
public static WebKit.WebKitBrowser mainBrowser = new WebKitBrowser();
And in an form, i've got now this code (thanks to Tearsdontfalls):
public void loginthen()
{
globalVars.mainBrowser.DocumentCompleted += mainBrowser_DocumentCompleted;
globalVars.mainBrowser.Navigate("http://www.somesite.com/");
}
void mainBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
var send = sender as WebKit.WebKitBrowser;
if (send.Url == e.Url)
{
MessageBox.Show("Inloggen");
globalVars.mainBrowser.Document.GetElementById("user").TextContent = "User Name";
}
}
But no messagebox shows up. But if i use an local (on the same form) webkit browser, i'm getting te MessageBox. But then the user field isn't filled in.
Even an breakpoint in the documentCompleted event, isn't triggerd. So it looks like the event listner isn't working...
So why is it not working?

You can simply create an event listener on the Document Completed Event on your Webbrowser, or you can create it dynamically like that:
globalVars.mainbrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(mainbrowser_DocumentCompleted);
Where mainbrowser_DocumentCompleted is the name of the void where you can do sth like this(I used the names of your provided code):
void browser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) {
var send = sender as WebKit.WebKitBrowser;
if (send.Url == e.Url) {
globalVars.mainBrowser.Document.GetElementById("user").TextContent = "User Name";
}
}

Adding the following piece of code let the events fire when the browser is in invisible mode.
using (Bitmap bmp = new Bitmap(webKitBrowser.Width, webKitBrowser.Height))
{
webKitBrowser.DrawToBitmap(
bmp,
new Rectangle(
webKitBrowser.Location.X,
webKitBrowser.Location.Y,
webKitBrowser.Width,
webKitBrowser.Height
)
);
}