VB.Net Webview2 How can I get html source code? - vb.net

Question

I sucessfully display a web site on WebView2 in my VB.net (Visual Studio 2017) project but can not get html souce code. Please advise me how to get html code.
My code:
Private Sub testbtn_Click(sender As Object, e As EventArgs) Handles testbtn.Click
WebView2.CoreWebView2.Navigate("https://www.microsoft.com/")
End Sub
Private Sub WebView2_NavigationCompleted(sender As Object, e As CoreWebView2NavigationCompletedEventArgs) Handles WebView2.NavigationCompleted
Dim html As String = ?????
End Sub
Thank you indeed for your advise in advance.

Answer 1

I've only just started messing with the WebView2 earlier today as well, and was just looking for this same thing. I did manage to scrape together this solution:
Dim html As String
html = Await WebView2.ExecuteScriptAsync("document.documentElement.outerHTML;")
' The Html comes back with unicode character codes, other escaped characters, and
' wrapped in double quotes, so I'm using this code to clean it up for what I'm doing.
html = Regex.Unescape(html)
html = html.Remove(0, 1)
html = html.Remove(html.Length - 1, 1)
Converted my code from C# to VB on the fly, so hopefully didn't miss any syntax errors.

Answer 2

Adding to #Xaviorq8 answer, you can use Span to get rid of generating new strings with Remove:
html = Regex.Unescape(html)
html = html.AsSpan()[1..^1].ToString();

Answer 3

I must credit #Xaviorq8; his answer was needed to solve my problem.
I was successfully using .NET WebBrowser and Html Agility Pack but I wanted to replace WebBrowser with .NET WebView2.
Snippet (working code with WebBrowser):
using HAP = HtmlAgilityPack;
HAP.HtmlDocument hapHtmlDocument = null;
hapHtmlDocument = new HAP.HtmlDocument();
hapHtmlDocument.Load(webBrowser1.DocumentStream);
HtmlNodeCollection nodes = hapHtmlDocument.DocumentNode.SelectNodes("//*[#id=\"apptAndReportsTbl\"]");
Snippet (failing code with WebView2):
using HAP = HtmlAgilityPack;
HAP.HtmlDocument hapHtmlDocument = null;
string html = await webView21.ExecuteScriptAsync("document.documentElement.outerHTML");
hapHtmlDocument = new HAP.HtmlDocument();
hapHtmlDocument.LoadHtml(html);
HtmlNodeCollection nodes = hapHtmlDocument.DocumentNode.SelectNodes("//*[#id=\"apptAndReportsTbl\"]");
Success withWebView2 and Html Agility Pack
using HAP = HtmlAgilityPack;
HAP.HtmlDocument hapHtmlDocument = null;
string html = await webView21.ExecuteScriptAsync("document.documentElement.outerHTML");
// thanks to #Xaviorq8 answer (next 3 lines)
html = Regex.Unescape(html);
html = html.Remove(0, 1);
html = html.Remove(html.Length - 1, 1);
hapHtmlDocument = new HAP.HtmlDocument();
hapHtmlDocument.LoadHtml(html);
HtmlNodeCollection nodes = hapHtmlDocument.DocumentNode.SelectNodes("//*[#id=\"apptAndReportsTbl\"]");

Answer 4

The accepted answer is on the right track. However, it's missing on important thing:
The returned string is NOT HTMLEncoded, it's JSON!
So to do it right, you need to deserialize the JSON, which is just as simple:
Dim html As String
html = Await WebView2.ExecuteScriptAsync("document.documentElement.outerHTML;")
html = Await JsonSerializer.DeserializeAsync(Of String)(html);