Exception when using AS in C #

Question

When recording

var e = element.NextSibling as HtmlElement;

I get an invalid exception. I thought that prevent cast exception and return null? because that is what I wanted / except. Or tell me, how can I get the value of e instead of an exception? or why did I get this exception when using the as keyword?

-edit- Fix this was an element. NextSibling throws an exception. How strange that his throwing exceptions cast when I havent tried it yet. I'm not sure how to check if the next brother exists. Error in NextSibling below

    Message "Unable to cast COM object of type 'System.__ComObject' to interface type 'IHTMLElement'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{3050F1FF-98B5-11CF-BB82-00AA00BDCE0B}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE))."  string

Answer 1

Are you sure this is a specific statement that throws an exception?

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var next = element.NextSibling;
var e = next as HtmlElement;

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