WebBrowser DocumentComplete Not Loaded on First Click VB.Net - vb.net

Question

I have a problem when click button 1st time, webbrowser.DocumentText always not loaded, but on 2nd or 3rd time clickings the documentText is ALWAYS loaded.
Glad if someone can advice.
my code as below:
Private Property pageready As Boolean = False
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button3.Click
WebBrowser1.Navigate(url)
WaitForPageLoad()
RichTextBox1.Text = WebBrowser1.DocumentText
Msgbox ("Document Loaded")
End Sub
Private Sub WaitForPageLoad()
AddHandler WebBrowser1.DocumentCompleted, New WebBrowserDocumentCompletedEventHandler(AddressOf PageWaiter)
While Not pageready
Application.DoEvents()
End While
pageready = False
End Sub
Private Sub PageWaiter(ByVal sender As Object, ByVal e As WebBrowserDocumentCompletedEventArgs)
If WebBrowser1.ReadyState = WebBrowserReadyState.Complete Then
pageready = True
RemoveHandler WebBrowser1.DocumentCompleted, New WebBrowserDocumentCompletedEventHandler(AddressOf PageWaiter)
End If
End Sub

Answer 1

Task Delay till the DocumentComplete loaded is the solustion for me.
Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button3.Click
WebBrowser1.Navigate(url)
Await ExampleMethodAsync()
RichTextBox1.Text = WebBrowser1.DocumentText
Msgbox ("Document Loaded")
End Sub
Async Function ExampleMethodAsync() As Task
' The following line simulates a task-returning asynchronous process.
Await Task.Delay(1750)
End Function

Answer 2

Here are two different ways you can dynamically wait for the WebBrowser to load the entire page:
Extending your Async/Await method to actually wait for the page to load you can use a ManualResetEvent. The MRE functions as a door: When you call Set() you open the door, when you call Reset() you close it, and when you call WaitOne(-1) you wait by the door for it to open (if it's closed).
Private DocumentCompletedResetEvent As New ManualResetEvent(False)
Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button3.Click
WebBrowser1.Navigate(url)
Await ExampleMethodAsync()
RichTextBox1.Text = WebBrowser1.DocumentText
Msgbox("Document Loaded")
End Sub
Async Function ExampleMethodAsync() As Task
DocumentCompletedResetEvent.Reset() 'Makes sure that the MRE is closed.
DocumentCompletedResetEvent.WaitOne(-1) 'Waits for it to open.
End Function
Private Sub WebBrowser1_DocumentCompleted(sender As System.Object, e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
If WebBrowser1.ReadyState = WebBrowserReadyState.Complete Then
DocumentCompletedResetEvent.Set() 'Opens the MRE.
End If
End Sub
The second method adds a temporary event handler to the DocumentCompleted event. Using Lambda expressions you may create an in-line method for the event handler.
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
WebBrowser1.Navigate(TextBox1.Text)
'Creates a temporary event handler.
Dim DocumentCompletedHandler As WebBrowserDocumentCompletedEventHandler = _
Sub()
If WebBrowser1.ReadyState = WebBrowserReadyState.Complete Then
RemoveHandler WebBrowser1.DocumentCompleted, DocumentCompletedHandler 'Removes the temporary event handler.
RichTextBox1.Text = WebBrowser1.DocumentText
Msgbox("Document Loaded")
End If
End Sub
AddHandler WebBrowser1.DocumentCompleted, DocumentCompletedHandler 'Adds the temporary event handler.
End Sub