[RESOLVED]Why can't I programatically fetch HTML from Webview2 (need to click button)

[pel11]

I can successfully fetch the inner text from google.com/index.html using the code below, but must click on a button. However, I would rather invoke an Await somehow to set the value of the sHTML string immediately after initbrowser(). However, I have tried using an Async Function "name" As Task, and awaited for sHTML to be set, but the CoreWebView2 is nothing (null), which throws an exception. Is there is a way to set the value of sHTML programatically right after I initialize the browser?

    Private Async Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Await initasync()
        Await initbrowser()
    End Sub

    Async Function initasync() As Task
        Await WebView21.EnsureCoreWebView2Async(Nothing)
    End Function

    Async Function initbrowser() As Task
        Await initasync()
        WebView21.CoreWebView2.Navigate("https://www.google.com/index.html")
    End Function

    Private Async Sub WebNavigation_Complete()
        Dim sHTML As String = Await WebView21.ExecuteScriptAsync("document.body.innerText;")
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        WebNavigation_Complete()
    End Sub

[techgnome]

Look at the events for the control... see if there is a Completed event that you can handle, in there, check the state, and if it's done, then you can access the contents.


-tg

[dday9]

Take a look at this example:

Imports Microsoft.Web.WebView2.Core

Public Class Form1
    Private Async Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Await WebView21.EnsureCoreWebView2Async(Nothing)
        WebView21.CoreWebView2.Navigate("https://www.google.com/index.html")

        Dim javascript = "window.addEventListener('load', () => window.chrome.webview.postMessage(document.body.innerText), false);"
        Await WebView21.ExecuteScriptAsync(javascript)
    End Sub

    Private Sub WebView21_WebMessageReceived(sender As Object, e As CoreWebView2WebMessageReceivedEventArgs) Handles WebView21.WebMessageReceived
        Dim content = e.TryGetWebMessageAsString()
        Console.WriteLine(content)
    End Sub

End Class

It sets up the load event handler using JavaScript, once the window loads it grabs the document's body's innerText and posts it back to the WebView2. The WebView2 then gets the message and prints it to the console.

[pel11]

Take a look at this example:

Imports Microsoft.Web.WebView2.Core

Public Class Form1
    Private Async Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Await WebView21.EnsureCoreWebView2Async(Nothing)
        WebView21.CoreWebView2.Navigate("https://www.google.com/index.html")

        Dim javascript = "window.addEventListener('load', () => window.chrome.webview.postMessage(document.body.innerText), false);"
        Await WebView21.ExecuteScriptAsync(javascript)
    End Sub

    Private Sub WebView21_WebMessageReceived(sender As Object, e As CoreWebView2WebMessageReceivedEventArgs) Handles WebView21.WebMessageReceived
        Dim content = e.TryGetWebMessageAsString()
        Console.WriteLine(content)
    End Sub

End Class

It sets up the load event handler using JavaScript, once the window loads it grabs the document's body's innerText and posts it back to the WebView2. The WebView2 then gets the message and prints it to the console.

Thanks - it worked once during the first debug run, but on the 2nd and 3rd debug runs, it didn't return anything. Is there a handle in windows that needs to be released, or should I dispose something via code? You could try this --> run it under debug once, then quit, then rerun and see what happens.

[dday9]

I'm not able to replicate that behavior. Every time I debug the code it prints the following:

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[pel11]

I'm not able to replicate that behavior. Every time I debug the code it prints the following:

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Thanks, it only happened once. After new runs, it works like a charm. No issues.