MonoTouch NSClassFromString

Question

I'm trying to use code such as the following Objective-C in MonoTouch:

if (NSClassFromString(@"ADBannerView"))

What is the equivalent in C#?

Basically I'm wanting to use iAd, but I need to check for the existance of ADBannerView and ADInterstitialAd , because they are not available on all versions of the OS. (And I'd rather do feature checking than iOS version checking)

I think this could be helpful in other situations as well.

Answer 1

A recent MonoTouch will always provide ADBannerView so you cannot the the C# equivalent of Type.GetType to query availability.

Normally a version check is the best way to check for features. Eg

bool available = UIDevice.CurrentDevice.CheckSystemVersion (4, 0);

will return true for any 4.0+ versions of iOS (4.0 being when ADBannerView was added to iOS).

A possible alternative (might not work in every case) is to create an instance and check it's handle. Since ObjC is message based sending init will return null (something a .NET constructor can't do). Eg

bool available = (new ADBannerView ().Handle != IntPtr.Zero);

Note that you probably best surround the above with using to dispose the view or integrate this inside the normal creation of your ADBannerView .

UPDATE : of course ap/invoke to NSClassFromString would do exactly the same as the ObjectiveC code :-)

Answer 2

This person asked the question and answered it. It looks like you need compiler flags:

Check this out: MonoTouch app with iAds runs on simulator, crashes on device

Otherwise you can Check for class in an assembly .

Lastly you can use the same google search I did: monotouch ADBannerView assembly

If this doesn't help, one of the guys at MonoTouch usually check for monotouch tagged questions and are really helpful.