Internet Reconnection script 'You cannot call a method on a null-valued expression' error

0
votes

I'm trying to have a script where when my Internet disconnects, it automatically reconnects and logs into the Wifi. However, there is an error where I cannot make the script login.

while (Test-Connection 8.8.8.8 -Quiet) {
}

netsh wlan connect wifi-name

$ie = New-Object -Com InternetExplorer.Application 
$ie.Visible = $false
$ie.Navigate("http://address/loginpage.php") 

$link = $ie.Document.GetElementById("btnLogin")
$link.Click()

$ie.Quit()

It returns with this error:

You cannot call a method on a null-valued expression.
At line:12 char:1
+ $link = $ie.Document.GetElementById("btnLogin")
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

You cannot call a method on a null-valued expression.
At line:13 char:1
+ $link.Click()
+ ~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

I have made sure the ID is correct as well:

Screenshot

1
powershell
You probably just need to wait until the page finished loading: do {Start-Sleep -Milliseconds 100} until ($ie.ReadyState -eq 4 -and -not $ie.Busy) - Ansgar Wiechers
thank you very much! That worked! - user10369648

1 Answers

1
votes

One possibility is that IE hasn't yet finished loading the page. This could be as it's trying to load proxy autoconfig file, contacting MS for new tab feed or the like.

Try adding a check for IE's busy property to see when it's ready with the document. Like so,

$ie = New-Object -com internetexplorer.application
$ie.visible = $false
$ie.navigate($url)

# Sleep while IE is busy. Check 10 times per second, adjust delay as needed
while($ie.Busy) { Start-Sleep -Milliseconds 100 }

# IE is not busy with document anymore, do stuff