Xamarin.Forms provides a way to quickly build native apps for iOS, Android, Windows and macOS, completely in C#.

Read more about the platform at https://www.xamarin.com/forms.

VS 2015 is required for developing Xamarin.Forms. If you do not already have it installed, you can download it here. VS 2015 Community is completely free. If you are installing VS 2015 for the first time, select the "Custom" installation type and select the following from the features list to install:

• C#/.NET (Xamarin v4.0.3)
• Universal Windows App Development Tools
• Windows 8.1 and Windows Phone 8.0/8.1 Tools

We also recommend installing Microsoft Visual Studio Emulator for Android as well as Emulators for Windows Phone 8.1. If you already have VS 2015 installed, you can verify that these features are installed by modifying the VS 2015 installation via the Control Panel.

After installing VS 2015, you will also need to install the following:

• Bing Maps SDK for Windows 8.1 Store apps -- you can find this in Tools > Extensions and Updates and searching for "bing" in the Online pane.
• Android SDKs -- you can install these via Tools > Android > Android SDK Manager.

Upon opening the Xamarin.Forms solution, you will find that there are a number of errors and warnings under the Error List pane; you can resolve this by changing the filter of Build + IntelliSense to Build Only. At this point, you should be able to successfully build the solution.

By default, the Xamarin.Forms.Controls project does not have a configuration for various API keys to access certain features on each platform (e.g. maps). When building the solution the first time, a controlgallery.config file will be generated inside that project, which looks like this:

Win8MapsAuthKey:
WinPhoneMapsAuthKey:
UWPMapsAuthKey:
InsightsApiKey:
WP8AppId:
WP8AuthToken:

You will have to obtain your own API keys for each of these services, inserted directly after the identifier (e.g. Win8MapsAuthKey:abcdefghijklmnopqrstuvwxyz). You can find out how to obtain each of these as follows:

• Win8MapsAuthKey, WinPhoneMapsAuthKey, and UWPMapsAuthKey at https://www.microsoft.com/maps/create-a-bing-maps-key.aspx
• InsightsApiKey at https://insights.xamarin.com/
• WP8AppId and WP8AuthToken at https://dev.windows.com/.

Due to the way that Android works, the maps API key cannot be injected at runtime. As a result, you will have to add this key to the MapsKey.cs file under Xamarin.Forms.ControlGallery.Android/Properties:

[assembly: Android.App.MetaData("com.google.android.maps.v2.API_KEY", Value = "INSERT_KEY_HERE")]

You can find out how to obtain a Google Maps API key here.

We follow the style used by the .NET Foundation, with a few exceptions:

• We do not use the private keyword as it is the default accessibility level in C#.
• We use hard tabs over spaces. You can change this setting in VS 2015 via Tools > Options and navigating to Text Editor > C# and selecting the "Keep tabs" radio option. In Visual Studio for Mac it's set via preferences in Source Code > Code Formatting > C# source code and disabling the checkbox for Convert tabs to spaces.
• Lines should be limited to a max of 120 characters (or as close as possible within reason). This may be set in Visual Studio for Mac via preferences in Source Code > Code Formatting > C# source code and changing the Desired file width to 120.

• How to Contribute

We use GitHub Issues to track issues. If at all possible, please submit a reproduction of your bug along with your bug report.