Beginning Xamarin and Xamarin.iOS

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I’ve recently started delving into using Xamarin and Xamarin.iOS to get an understanding of its capabilities and see what I could do with it. After my first little app, I have to say it is really impressive what the people at Xamarin have done!

I’m coming at this from years of experience in C# and WPF/Silverlight/XAML and I wanted to describe my initial findings. For this post I plan to cover the general setup.

Installation

My goal was to have an iPad application that does something similar to a Master-Detail set of views where I could display a collection of images. Because of this I wanted to get a grasp on both Xamarin Studio and the Visual Studio integration so I installed Xamarin for Windows (on my primary dev machine) and Xamarin for OS X (on a Mac Mini we have at our office) from here. NOTE: On Windows 8 run the Xamarin installer as Administrator otherwise it will error out near the end. The installation took a while because it downloaded everything that I needed to develop for iOS (and for Android since I wanted to look into that in the future too.), but once everything was installed I was able to start developing instantly.

The installation guides for Xamarin.iOS, located here, provided excellent instruction for hooking up Visual Studio 2012 to remote debug on the Mac Mini (Section: 6.2. Connecting to the Mac Build Host), and the Xamarin services that were installed made it so that I found and connected to the Mac immediately. On another note, Synergy is an amazing tool to use to share your keyboard and mouse between the 2 devices. You need to make sure both machines are on the same network though in order for it to work (quickly at least).

Solution Setup

With Xamarin installed, I decided to get my feet wet by following Xamarin’s Hello, iPhone guide. (They’ve done a very nice job with their guides covering a nice range of topics.) For someone who has never developed in Xcode (and is pretty much a Mac beginner) this provided a nice tutorial of the tool.

With a general idea of how to get started, I created my solution in VS 2012 and on the Mac I used “Finder” to connect to my machine and open up the solution in Xamarin Studio. I’ve found that if I want to use Xcode’s Interface Builder to design my UI I need to add the iPad View Controller via Xamarin Studio, since adding it in Visual Studio didn’t create the .xib file.

My next step was to set up a core library, since I desire to try Xamarin’s Android functionality in the future, to enable code reuse. Xamarin is currently developing support for referencing Portable Class Libraries (PCLs), but until they’ve got that functioning we have to go more manual routes. I created the PCL to hold my core files (model objects primarily), but went the route of linking to all those files in the iOS project. Once I work on the Android counterpart I’ll be able to update with whether I think it’s the right way to go.

EDIT: With the release of Xamarin.iOS 7.0.1, they’ve apparently fixed the PCL build issue I was running into. So I was able to remove the links to all the files and reference the PCL library instead!

Debugging

It is extremely nice to be able to dev and debug in VS 2012 while connected to the iOS simulator on the Mac. When running into exceptions being thrown, I found that, if it wasn’t immediately apparent as to what the exception was caused by, debugging from Xamarin Studio on the Mac provides better exception information.

I’ll go into more detail on discoveries I ran into in other posts, but overall the development process using Xamarin and Xamarin.iOS has been very interesting and enjoyable. I would definitely recommend it.

Blend for Visual Studio 2012 Platform Errors

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With the recent release of Visual Studio 2012 Update 2 there is finally a real release version of Blend that can support WPF projects on .NET 4.5 in the form of Blend for Visual Studio 2012 (installed with the VS update package). Unfortunately there is a nasty and obscure error that can come up unexpectedly in applications that work fine in Visual Studio and at runtime.

The issue manifests as the dreaded Invalid Markup screen:

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and a series of errors in XAML of the form “X is not supported in a Windows Presentation Foundation (WPF) project.” for every element in your project’s XAML:

List of Blend design surface errors from incorrectly unsupported elements.

The cause of the issue is a problem with how Blend loads solution configurations. Continue reading

Unit Test filtering for TFS builds using Test Explorer in VS 2012

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One of the major new features in Visual Studio 2012 is the Text Explorer tool window, which consolidates 2010’s Test View and Test Results windows and adds support for using different testing frameworks together in one place. There are definitely some positive aspects to Test Explorer in comparison to its predecessors, but as a completely new piece of functionality it unfortunately left out some key features that were previously available.

One of the places it fell short was in filtering of tests to enable running a specific subset of the tests in your solution, especially when working with a set of tests set up for TFS’s Team Build. When working with small sets of tests it could be a minor annoyance, but working with hundreds or thousands of tests made it basically unusable. Thanks to Visual Studio’s new release model of frequent updates, these shortcomings are already starting to be addressed with November’s Update 1.

The preferred method of specifying tests to run with builds in TFS is by using attributes on test methods, specifically the Priority and TestCategory attributes. VS2010’s Test View displays a configurable grid listing all available tests in the open solution.
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