How does IsMobileDevice work?

Question

MSDN makes it sound so easy to detect a mobile browser:

if (Request.Browser["IsMobileDevice"] == "true" ) 
{
    Response.Redirect("MobileDefault.aspx");
}

Actually, it looks like you can also just check Request.Browser.IsMobileDevice. But how does this actually work? I don't even have a .browser file... what's going on behind the scenes here? Are there some built-in defaults for ASP.NET 2.0?

Answer 1

A number of *.browser files are shipped with .NET:

C:\Windows\Microsoft.NET\Framework\v2.0.50727\CONFIG\Browsers

The runtime uses regular expressions from the *.browser files to match against the incoming User-Agent string, and then sets a bunch of properties based on each match it finds (there can be several in the hierarchy).

If you need in-depth mobile device support, consider installing the MDBF, which adds support for about 400 devices:

http://mdbf.codeplex.com/

Answer 2

Now, after 4 years, it's even more simple

Request.Browser.IsMobileDevice

Answer 3

Since for most sites, it is actually the size of the screen that matters and not so much the capabilities (at least when talking about modern phones with things like Safari and Chrome on them) wouldn't checking the resolution make the most sense?

Request.Browser.ScreenPixelsHeight

and

Request.Browser.ScreenPixelsWidth

Answer 4

I wouldn't rely on the MSDN link, there is no common standard unfortunately for mobile browsers and many try to mimic their non-mobile counterparts. Also it will return true if it doesn't recognize. See this link.