This is a super important subject that is kind of like adaptive web pages as we want to have our UI adapt to the various Apple form factors. I would encourage reading Apples document at Beginners like me forget about this and design for the phone that they have e.g my 6. It looks great on the 6 but like crud on the other devices. Now this is possible to do in Visual Studio but XCode is so much better at this. Cannot believe I said this as I am a lifelong MS developer but Apple has had so much more time to refine their tool and it is great. However it is possible to use Visual Studio and I try showing you in this video. video
after all my praise I got hit by this error yesterday am and I swear I made no changes to my Windows or Mac setup. My VS build stopped functioning so I went over to my Mac and ran a simple XCode build and it failed too with this error. My builds were motoring along up this point but turns out that I needed to update XCode to 9.1 for my IOS 11.1.1. Nasty as I said there were no changes to my environment so not sure process suddenly woke up and ruined my morning!
To do IOS development you must have access to a Mac either your own or something like MacInCloud , of course the problem with the latter is attaching an iPhone if you want to see your app on the real device. I went out and bought a Mac Mini which was the cheapest solution I could find. I did not want to invest a lot as had no idea where this was going and had always been a Windows person. Now I think I would get a MacBook as the Mac Mini limits my portability which is important to me as I move around. For the Mac Mini I initially went with the standard mini offering but it was sluggish so upgraded to the max RAM I could get a 512G solid state drive. On Windows I installed Xamarin which of course runs in Visual Studio Community edition and is free (great move by Microsoft) . I then have both my machines on the same WIFI network and am in business. Of course i had a learning challenge on the Mac but that is half the fun. I must admit that the Mac experience was not nearly as painful as I envisioned. Kind of like my first date! I had to download and install XCode but again that is free. After initially being overwhelmed by XCode as there are so many options I really like it. Such a powerful tool and you should learn to like it to for like cough syrup it can be good for you (more on that later). For completeness sake I also installed Visual Studio for Mac as it is needed to move files into XCode. I might be wrong on the last statement as there might be a better solution for this. I also make sure I am running with the latest version of everything like IOS 11.1.1 and XCode 9.1 as of this blog post.