NullReferenceException on coded HtmlControl find

[Bret]

Hi

I receive the error "System.NullReferenceException: Object reference not set to an instance of an object." on a coded step that logs a user out of web application in step 5, and then waits until the "thank you" text is displayed on the subsequent page until continuing with the script. The error is thrown on line 8. I construct the ThankYouSignOut object in line 7 almost exactly the same as the SignOutLink in step 2, so I'm at a loss as to why it's passing on step 2-5, but failing on 8. Any help would be appreciated!

 

1.ActiveBrowser.Window.SetFocus
2.Dim SignOutLink AS HtmlAnchor = ActiveBrowser.Find.ByExpression(Of HtmlAnchor)(new HtmlFindExpression("tagname=a", "href=~logout"))
3.SignOutLink.Wait.ForExists(30000)
4.SignOutLink.ScrollToVisible(ArtOfTest.WebAii.Core.ScrollToVisibleType.ElementTopAtWindowTop)
5.SignOutLink.MouseClick
6.ActiveBrowser.Window.SetFocus
7.Dim ThankYouSignOut AS HtmlControl = ActiveBrowser.Find.ByExpression(Of HtmlControl)(new HtmlFindExpression("tagname=p","TextContent=^Thank you for using"))
8.ThankYouSignOut.Wait.ForExists(30000)

 

[Bret]

Nevermind. Of course as soon as I post to the forum I find the answer to my question.

Manager.ActiveBrowser.RefreshDomTree

[Boyan Boev]

Hi Bret,

Happy to hear that!

If you need further assistance please let us know.

Regards,
Boyan Boev
Telerik

 

[evan]

To fully understand why a NullReferenceException is thrown, it is important to know the difference between value types and reference types.

So, if you're dealing with value types, NullReferenceExceptions can not occur. Though you need to keep alert when dealing with reference types!

Only reference types, as the name is suggesting, can hold references or point literally to nothing (or 'null'). Whereas value types always contain a value.

Reference types (these ones must be checked):

dynamic
object
string

Value types (you can simply ignore these ones):

Numeric types
Integral types
Floating-point types
decimal
bool
User defined structs

[Daniel Djambov]

Hi,

Thank you for the feedback on this issue.

To my understanding there is currently no problem with the product that requires additional input.

If my assumption is wrong, please let me know how we can help you further.

Best Regards,
Daniel Djambov
Progress Telerik