Specified cast not valid using webbrowser control

[matty95srk]

I'm using the Telegram.bot package from nuget and getting the last message as a string from the client. I want then to set it as the attribute of a textbox on a webpage with the control WebBrowser. I'm working on framework 4.7 for Windows Form.

The code I'm using is:

Private Sub InsertLink(link as string)
    
         MsgBox(link)
    
         WebBrowser1.Document.GetElementById("video_url").SetAttribute("value", link)
          WebBrowser1.Document.GetElementById("submitButton").InvokeMember("click")
          Catch ex As Exception
          MsgBox(ex.Message)
         End Try
     End Sub
    
     Private Sub form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
         Dim botid As String = "my bot api"
         Dim bot As New TelegramBotClient(botid)
    
         Dim cts = New CancellationTokenSource()
         Dim options = New ReceiverOptions With {
             .AllowedUpdates = Array.Empty(Of UpdateType)()
         }
         bot.StartReceiving(updateHandler:=AddressOf HandleUpdateAsync, errorHandler:=AddressOf HandleErrorAsync, options, cts.Token)
         Console.ReadLine()
     End Sub
     Public link As String
    
     Private Async Function HandleUpdateAsync(botClient As ITelegramBotClient,
                                         update As Update,
                                         cancellationToken As CancellationToken) As Task
    
         Try
             If update.Message IsNot Nothing Then
    
                 link = update.Message.[text]
                 InsertLink(link)
                   
    
             End If
         Catch ex As Exception
             MsgBox(ex.Message)
         End Try
     End Function
    
     Private Function HandleErrorAsync(botClient As ITelegramBotClient,
                                 exception As Exception,
                                 cancellationToken As CancellationToken) As Task
         Console.WriteLine(exception)
         Return Task.CompletedTask
    
     End Function
 End Class

The code, eventhough is not fully async ( since VS shows a message about missing awaits), works. Which means it receives correctly the message from the client as a String.



It also correctly pass the message as a parameter to the Sub InsertLink. But after that, it won't fill the textbox on the webpage.

I want to specify two things:

• I am SURE about the code that Set the Attribute in the webbrowser ( gif under );
• I am SURE about the code that gets the message from telegram client that receive correctly the message as a string type ( gif under ).

Now let's pass to the gifs I recorded. Using breakpoints during debugs, line by line

https://i.stack.imgur.com/Tm0gw.gif

the following gif 2 shows the real functioning of the Set Attribute using a simple button and calling the Sub InsertLink with InsertLink("hello") and the message box ( in italian - Specifiec cast is not valid ) of error when sending a message from the client
https://imgur.com/a/jH0uJuw

And the last gif shows a test I've tried using some window in debug, where I suppose there is a cross thread issue since its written in the debug window Local > Accessibility Object > Message = "Cross Thread, trying to access to form 1 from a different thread".. but seriously I don't know what the issue is, so I just keep scrolling if it can help you to find the issue.

https://i.stack.imgur.com/tsnB4.gif

I'm really struggling with this issue and I'm not able to insert the text from the client to the webbrowser.

the only line on stack trace is :

Exception thrown: 'System.InvalidCastException' in System.Windows.Forms.dll

and the line Throw New System.Exception inside the catch block of the Private Sub InsertLink fires only

Exception thrown: 'System.Exception' in YoutubeToMp3.exe