C# Navigate to Anchors in WebBrowser control - c#

We have a web browser in our Winforms app to nicely display history of a selected item rendered by xslt.
The xslt is writing out <a> tags in the outputted html to allow the webBrowser control to navigate to the selected history entry.
As we are not 'navigating' to the html in the strict web sense, rather setting the html by the DocumentText, I can't 'navigate' to desired anchors with a #AnchorName, as the webBrowser's Url is null (edit: actually on completion it is about:blank).
How can I dynamically navigate to Anchor tags in the html of the Web Browser control in this case?
EDIT:
Thanks sdolphion for the tip, this is the eventual code I used
void _history_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
_completed = true;
if (!string.IsNullOrEmpty(_requestedAnchor))
{
JumpToRequestedAnchor();
return;
}
}
private void JumpToRequestedAnchor()
{
HtmlElementCollection elements = _history.Document.GetElementsByTagName("A");
foreach (HtmlElement element in elements)
{
if (element.GetAttribute("Name") == _requestedAnchor)
{
element.ScrollIntoView(true);
return;
}
}
}


I am sure someone has a better way of doing this but here is what I used to accomplish this task.
HtmlElementCollection elements = this.webBrowser.Document.Body.All;
foreach(HtmlElement element in elements){
string nameAttribute = element.GetAttribute("Name");
if(!string.IsNullOrEmpty(nameAttribute) && nameAttribute == section){
element.ScrollIntoView(true);
break;
}
}


I know this question is old and has a great answer, but this hasn't been suggested yet, so it might be useful for others that come here looking for an answer.
Another way to do it is use the element id in the HTML.
<p id="section1">This is a test section</p>
Then you can use
HtmlElement sectionAnchor = webBrowserPreview.Document.GetElementById("section1");
if (sectionAnchor != null)
{
sectionAnchor.ScrollIntoView(true);
}
where webBrowserPreview is your WebBrowser control.
Alternatively, sectionAnchor.ScrollIntoView(false) will only bring the element on screen instead of aligning it with the top of the page

Related

C# Click on HtmlElement With no ID only Class

I am not using selenium nor anything else, i just want to do it on the webbrowser on the windows form application.
I have a windows form application and i want to click on a button with code but there is no ID.
I tried using a lot of different things found on this websites forums, but none of this works.

Have you tried using WebBrowser.GetElementByTagName("div") and then checking each element against attribute type=submit?
Your code should look something like
HtmlElement submit = FindSubmitElement(webBrowser1.Document);
submit?.InvokeMember("submit");
public HtmlElement FindSubmitElement(HtmlDocument document)
{
HtmlElementCollection elems = document.GetElementsByTagName("div"); // since your tag is div
// this will return collection, even in case there is just one div, find the first one, having an attribute 'type' with value 'submit'
foreach (HtmlElement elem in elems)
{
string type = elem.GetAttribute("type");
if (!string.IsNullOrEmpty(type) && type == "submit")
{
return elem; // if div tag with attribute type is found exit and return that html element
}
}
return null; // if no div tags found with an attribute 'type' return null
}
Check more on GetElementsByTagName method on the MSDN docs. Code is taken from there and adjusted to your need.

WinForms Control Not working

I am trying to read in the first description in the first row. However, for some reason my if statement is never becoming true. Here is the html code that has the class im trying to read from. I gave a picture of it. Below that is the actual code im running. There is a first page that I login to and then input the part number. This then takes me to this page where you see the html code in the picture. I then need to grab the description of the part number. I included a picture of the website I am grabbing the description from. In order to give you a better Idea of what's happening. Also, I have a web browser component in my code that I am using. Can you point out why its not working? Thanks.
var secondPage = webBrowser1.Document;
foreach (HtmlElement element in secondPage.All)
{
if (element.GetAttribute("className") == "SE-Content-PartSearch-Grid-Row-Description")
{
messagebox.Show("Found it");
}
}
ActualWebsite
HTMLCODE

I suggest that you put a breakpoint on the "if" statement. It will perhaps be easier to see what is going on if you modify the code slightly:
var secondPage = webBrowser1.Document;
foreach (HtmlElement element in secondPage.All)
{
String className = element.GetAttribute("className");
if (className == "SE-Content-PartSearch-Grid-Row-Description")
{
messagebox.Show("Found it");
}
}

how to get the input element by class using mshtml.IHTMLDocument2

I'm new in using mshtml package library from .NET and, as such, I'm struggling to read the input element rendered in WPF web browser control.
I have researched through the internet and stumbled on this link. How to get the value of an input box of the webbrowser control in WPF?
But in my case, I want to read/get the input element by class, not by name attribute. Unfortunately, I know that GetElementByClass is not an option in WebBrowser.Document
This is my code - When I tried to run the debugger, the code doesn't continue inside the foreach loop ):
private void browser_LoadCompleted(object sender, NavigationEventArgs e)
{
IHTMLElementCollection elementCollection;
IHTMLDocument3 dom = (IHTMLDocument3)browser.Document;
elementCollection = dom.getElementsByTagName("input");
foreach (HtmlElement item in elementCollection)
{
if (item.OuterHtml.Contains("input_search"))
{
//Do something else here...
}
}
}
A screen capture of the DOM of the page
Any help is greatly appreciated.

How can I inject inline styling into a Document being loaded in my WPF WebBrowser?

I've been trying to use mshtml to modify a third party web api. Right now I am trying to change the display property on two elements to none so they will be invisible.
I know their id's.
The first one is an img and the id is zendbox_close. The second is a div and the id is zenbox_scrim.
The html looks like this
<div class="zenbox_header">
<img id="zenbox_close"></img>
</div>
...
<div id="zenbox_scrim...></div>
All I want to do is add in some inline styling so it looks like this
<div class="zenbox_header">
<img id="zenbox_close" style="display:none;"></img>
</div>
...
<div id="zenbox_scrim style="display:none;"...></div>
In my code behind for the WPF WebBrowser that is opening up the webpage, I have gotten this far:
IHTMLDocument3 doc = (IHTMLDocument3)this._browser.Document;
IHTMLImgElement element = (IHTMLImgElement)doc.getElementById("zenbox_close");
I saw in another post someone was talking about injecting scripts and they said you can use
IHTMLElement scriptEl = doc.CreateElement("script");
I am not sure what the HTML element analog to this would be though. Also I had to use IHTMLDocument3 to use the method getElementById, but that class doesn't appear to contain anything similar to CreateElement().
My question is how can I inject inline styling into a Document being loaded in my WPF WebBrowser?

Yes you can manipulate styles inline.
A good way to do this is to work with the IHTMLStyle or IHTMLCurrentStyle interfaces when working with an IHTMLElement. There are some differences with the values reflected by those two and they are not always synch'd. A better explanation of why that is:
IHTMLStyle vs IHTMLCurrentStyle
Code sample would look like:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
wb.LoadCompleted += wb_LoadCompleted;
wb.Source = new Uri("http://www.google.com");
}
void wb_LoadCompleted(object sender, NavigationEventArgs e)
{
var doc = wb.Document as HTMLDocument;
var collection = doc.getElementsByTagName("input");
foreach (IHTMLElement input in collection)
{
dynamic currentStyle = (input as IHTMLElement2).currentStyle.getAttribute("backgroundColor");
input.style.setAttribute("backgroundColor", "red");
}
}
}

How to display the string html contents into webbrowser control?

I have a C# win app program. I save the text with html format in my database but I want to show it in a webbrowser to my user.How to display the string html contents into webbrowser control?

Try this:
webBrowser1.DocumentText =
"<html><body>Please enter your name:<br/>" +
"<input type='text' name='userName'/><br/>" +
"<a href='http://www.microsoft.com'>continue</a>" +
"</body></html>";

Instead of navigating to blank, you can do
webBrowser1.DocumentText="0";
webBrowser1.Document.OpenNew(true);
webBrowser1.Document.Write(theHTML);
webBrowser1.Refresh();
No need to wait for events or anything else. You can check the MSDN for OpenNew, while I have tested the initial DocumentText assignment in one of my projects and it works.

As commented by Thomas W. - I almost missed this comment but I had the same issues so it's worth rewriting as an answer I think.
The main issue being that after the first assignment of webBrowser1.DocumentText to some html, subsequent assignments had no effect.
The solution as linked by Thomas can be found in detail at http://weblogs.asp.net/gunnarpeipman/archive/2009/08/15/displaying-custom-html-in-webbrowser-control.aspx however I will summarize below in case this page becomes unavailable in the future.
In short, due to the way the webBrowser control works, you must navigate to a new page each time you wish to change the content. Therefore the author proposes a method to update the control as:
private void DisplayHtml(string html)
{
webBrowser1.Navigate("about:blank");
if (webBrowser1.Document != null)
{
webBrowser1.Document.Write(string.Empty);
}
webBrowser1.DocumentText = html;
}
I have however found that in my current application I get a CastException from the line if(webBrowser1.Document != null). I'm not sure why this is, but I've found that if I wrap the whole if block in a try catch the desired effect still works. See:
private void DisplayHtml(string html)
{
webBrowser1.Navigate("about:blank");
try
{
if (webBrowser1.Document != null)
{
webBrowser1.Document.Write(string.Empty);
}
}
catch (CastException e)
{ } // do nothing with this
webBrowser1.DocumentText = html;
}
So every time the function to DisplayHtml is executed I receive a CastException from the if statement, so the contents of the if statement are never reached. However if I comment out the if statement so as not to receive the CastException, then the browser control doesn't get updated. I suspect there is another side effect of the code behind the Document property which causes this effect despite the fact that it also throws an exception.
Anyway I hope this helps people.

For some reason the code supplied by m3z (with the DisplayHtml(string) method) is not working in my case (except first time). I'm always displaying html from string. Here is my version after the battle with the WebBrowser control:
webBrowser1.Navigate("about:blank");
while (webBrowser1.Document == null || webBrowser1.Document.Body == null)
Application.DoEvents();
webBrowser1.Document.OpenNew(true).Write(html);
Working every time for me. I hope it helps someone.

Simple solution, I've tested is
webBrowser1.Refresh();
var str = "<html><head></head><body>" + sender.ToString() + "</body></html>";
webBrowser1.DocumentText = str;

webBrowser.NavigateToString(yourString);

Here is a little code. It works (for me) at any subsequent html code change of the WebBrowser control. You may adapt it to your specific needs.
static public void SetWebBrowserHtml(WebBrowser Browser, string HtmlText)
{
if (Browser != null)
{
if (string.IsNullOrWhiteSpace(HtmlText))
{
// Putting a div inside body forces control to use div instead of P (paragraph)
// when the user presses the enter button
HtmlText =
#"<html>
<head>
<meta http-equiv=""Content-Type"" content=""text/html; charset=UTF-8"" />
</head>
<div></div>
<body>
</body>
</html>";
}
if (Browser.Document == null)
{
Browser.Navigate("about:blank");
//Wait for document to finish loading
while (Browser.ReadyState != WebBrowserReadyState.Complete)
{
Application.DoEvents();
System.Threading.Thread.Sleep(5);
}
}
// Write html code
dynamic Doc = Browser.Document.DomDocument;
Doc.open();
Doc.write(HtmlText);
Doc.close();
// Add scripts here
/*
dynamic Doc = Document.DomDocument;
dynamic Script = Doc.getElementById("MyScriptFunctions");
if (Script == null)
{
Script = Doc.createElement("script");
Script.id = "MyScriptFunctions";
Script.text = JavascriptFunctionsSourcecode;
Doc.appendChild(Script);
}
*/
// Enable contentEditable
/*
if (Browser.Document.Body != null)
{
if (Browser.Version.Major >= 9)
Browser.Document.Body.SetAttribute("contentEditable", "true");
}
*/
// Attach event handlers
// Browser.Document.AttachEventHandler("onkeyup", BrowserKeyUp);
// Browser.Document.AttachEventHandler("onkeypress", BrowserKeyPress);
// etc...
}
}

Old question, but here's my go-to for this operation.
If browser.Document IsNot Nothing Then
browser.Document.OpenNew(True)
browser.Document.Write(My.Resources.htmlTemplate)
Else
browser.DocumentText = My.Resources.htmlTemplate
End If
And be sure that any browser.Navigating event DOES NOT cancel "about:blank" URLs. Example event below for full control of WebBrowser navigating.
Private Sub browser_Navigating(sender As Object, e As WebBrowserNavigatingEventArgs) Handles browser.Navigating
Try
Me.Cursor = Cursors.WaitCursor
Select Case e.Url.Scheme
Case Constants.App_Url_Scheme
Dim query As Specialized.NameValueCollection = System.Web.HttpUtility.ParseQueryString(e.Url.Query)
Select Case e.Url.Host
Case Constants.Navigation.URLs.ToggleExpander.Host
Dim nodeID As String = query.Item(Constants.Navigation.URLs.ToggleExpander.Parameters.NodeID)
:
:
<other operations here>
:
:
End Select
Case Else
e.Cancel = (e.Url.ToString() <> "about:blank")
End Select
Catch ex As Exception
ExceptionBox.Show(ex, "Operation failed.")
Finally
Me.Cursor = Cursors.Default
End Try
End Sub

The DisplayHtml(string html) recommended by m3z worked for me.
In case it helps somebody, I would also like to mention that initially there were some spaces in my HTML that invalidated the HTML and so the text appeared as a string. The spaces were introduced (around the angular brackets) when I pasted the HTML into Visual Studio. So if your text is still appearing as text after you try the solutions mentioned in this post, then it may be worth checking that the HTML syntax is correct.

Categories

Resources