Programatically clicking an html button by vb.net - vb.net

Question

I have to click a HTML button programatically which is on the 3rd page of the website . The button is without id. It has just name type and value . The HTML code of the button is given below
<FORM NAME='form1' METHOD='post' action='/dflogin.php'>
<INPUT TYPE='hidden' NAME='txtId' value='E712050-15'>
<INPUT TYPE='hidden' NAME='txtassId' value='1'><INPUT TYPE='hidden' NAME='txtPsw' value='HH29'>
<INPUT TYPE='hidden' NAME='txtLog' value='0'><h6 align='right'>
<INPUT TYPE='SUBMIT' NAME='btnSub' value='Next' style='background-color:#009900; color:#fff;'></h6>
</FORM>
i am using the following code to click it
For Each webpageelement As HtmlElement In allButtons
If webpageelement.GetAttribute("value") = "Start" Then
webpageelement.InvokeMember("click")
End If
Next
But i cant able to click it . I am using the vb.net 2008 platform. Can anyone tell me the solution to click it?

Answer 1

Try invoking Submit on the Form rather than click on the Input.
EDIT: Oops, HTMLElementCollection does not implement the generic IEnumerable. Try this instead:
Dim l_forms = WebBrowser1.Document.GetElementsByTagName("form")
If l_forms.Count > 0 Then
l_forms.Item(0).InvokeMember("submit")
End If

Answer 2

Dim Elems As HtmlElementCollection
Dim WebOC As WebBrowser = WebBrowser1
Elems = WebOC.Document.GetElementsByTagName("input")
For Each elem As HtmlElement In Elems
elem.InvokeMember("click")
Next

Answer 3

I spent quite a while trying to find an answer to this. I never realized that you can invoke a click using javascript. Once I read that the solution becomes very easy:
Public Function clickbyid(ByVal id)
If TheBrowser.Document.GetElementById(id) IsNot Nothing Then
Dim Headers As String = "" 'insert headers if you want to
TheBrowser.Navigate("javascript:document.getElementById('" & id & "').click();", "_self", Nothing, Headers)
'This keeps the function active until the browser has finished loading
Do While TheBrowser.ReadyState <> WebBrowserReadyState.Complete
Application.DoEvents()
Loop
Return 1
Else
MessageBox.Show("Could not find link by id" & id)
Return Nothing
End If
End Function
You may have to change "TheBrowser" to "WebBrowser1".
If you don't want to return a result then simply change it to public sub and remove the return statements.
If the htmlelement does not have an id then use the following functions to add one
Public Function clickbyelement(ByVal theButton As HtmlElement)
Try
'Generate a unique id to identify the element
Dim randomID = "vbAdded" & GetRandom(10000, 100000).ToString
'check to make sure the ID does not already exist
While TheBrowser.Document.GetElementById(randomID) IsNot Nothing
randomID = "vbAdded" & GetRandom(10000, 100000).ToString
End While
'add the ID to the element
theButton.SetAttribute("id", randomID)
'click
clickbyid(randomID)
Return True
Catch ex As Exception
Return False
End Try
End Function
Public Function GetRandom(ByVal Min As Integer, ByVal Max As Integer) As Integer
' by making Generator static, we preserve the same instance '
' (i.e., do not create new instances with the same seed over and over) '
' between calls '
Static Generator As System.Random = New System.Random()
Return Generator.Next(Min, Max)
End Function
Thanks to Dan Tao for the random number: https://stackoverflow.com/a/2677819/381273
Tested and working!

Answer 4

It sounds like you are trying to do a client-side action - click the button when operating on the server (VB code). This will not work.
So, either use Javascript document.form1.submit() or call the VB sub that is connected to the button btnsub.click (or whatever you named it).

Answer 5

The Solution:
WebBrowser1.Navigate("UrlHere!")
'wait till the page is laoded
Do While WebBrowser1.ReadyState <> WebBrowserReadyState.Complete
Application.DoEvents()
Loop
WebBrowser1.Document.Body.InnerHtml = Replace(WebBrowser1.Document.Body.InnerHtml, "NAME='btnSub'", "NAME='btnSub' id='btnSub'") 'insert id into youre button
WebBrowser1.Document.GetElementById("btnSub").InvokeMember("click") 'click on btnSub
;)