How can I use "is" to determine if the value of a parameter is a type of class?

Question

I am trying to test if the current page of my application is the CardsTabPage like this:

_page.CurrentPage is Japanese.CardsTabPage

However it always returns false even though when I use the debugger it seems like it should read true. Here's what I see when I hover over CurrentPage:

Does anyone have any idea what might be wrong and why this:

is not returning true?

I also tried this but it doesn't work:

score 1 · Accepted Answer · answered Apr 28 '19 at 06:55

You need to access _page.CurrentPage.CurrentPage, but you can't do that directly because the compile-time type of _page.CurrentPage is just Page. You need to first cast that to NavigationPage, then use the CurrentPage property of that.

If your compiler supports pattern matching, you can do that as:

if (_page.CurrentPage is NavigationPage np && np.CurrentPage is Japanese.CardsTabPage)

Otherwise you'd need something like:

if (_page.CurrentPage is NavigationPage &&
    ((NavigationPage) _page.CurrentPage).CurrentPage is Japanese.CardsTabPage)

How can I use "is" to determine if the value of a parameter is a type of class?

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