如何检查Xamarin iOS中是否存在某种方法/类/ API？

Question

In iOS 6 & 7 Compatibility Tips it is recommended to check for a specific API like this

public static bool IsiOS7 {
  get { return UIDevice.CurrentDevice.CheckSystemVersion (7, 0); }
}

if(Util.IsiOS7) {
  //Call iOS 7 API
} else {
  //Call iOS 6.1 or earlier API
}

The same should go for iOS 8. Now I read that you should check if a certain method or class exists instead of version checking. Here RespondsToSelector comes in. That should be something like this

if (RespondsToSelector(new Selector("edgesForExtendedLayout")))
       EdgesForExtendedLayout = UIRectEdge.None;

But how would one check if a whole class exists like UIAlertController ? There is no NSClassFromString like in Objective-C. I also saw something like this in Objective-C

if ([UIAlertController class]){
    // ...
}

Would something like this do the trick?

Type type=Type.GetType("UIAlertController");
if(type!=null)
{
    // iOS 8 API
}else{
    // iOS 7 or lower
}

How would one do that in C#? Or which other ways exists to check for UIAlertController , UISearchController , ... and so on.

Answer 1

Do this:

using MonoTouch.ObjCRuntime;
bool hasUIAlertController = Class.GetHandle ("UIAlertController") != IntPtr.Zero;
if (hasUIAlertController) {
    // iOS 8
} else {
    // iOS 7 or lower
}