Everything compiles just fine, but when the app pops up it just shows a white map with the esri logo in the bottom left. Anyone get any farther with this?
We intend to certify the next release (version 10.2.6) of the ArcGIS Runtime SDK for .NET for use developing apps on Windows 10 that target .NET 4.5+ (Desktop), Store 8.1, and Phone 8.1. A Windows Store app that targets 8.1 will work on a device running Windows 10. Version 10.2.6 of the ArcGIS Runtime SDK for .NET will be made available in the coming weeks.
With respect to building Windows Universal apps for Windows 10 using Visual Studio 2015, we would like to support use of the Windows Store API included in 10.2.6. According to Microsoft an extension SDK that targets 8.1 can be used in a Windows 10 Universal app. However, due to some technical changes between Windows 8.1 and Windows 10, we may not be able to support this combination. We will have more information when the commercial release of Windows 10 is made available at the end of July.
Just to add: We reported the issues we found to Microsoft, and they confirmed them and told us later they have been fixed. However we don't have the bits to verify this, so no guarantees.
The main issue we found with the non-native compiler. For the most part, if you enable the .NET Native compiler (typically using the release configuration or enabling it in your project settings), things seems to work, however note that build times are much much slower. Also note that running on a Phone doesn't work at this point at all.
As Rex mentions, we haven't done any full certification and can't really begin this until Windows 10 is final, but we've done what we can wrt to reporting the issues we found and have been working closely with Microsoft on this.
The next major release (AKA Quartz) will have support for UWP out of the box.
...follow-up: We got confirmed from Microsoft that an 8.1 SDK using native dependencies (like the ArcGIS Runtime) will _not_ work in an UWP on Windows 10 Mobile.
We are still hoping we can certify our SDK for UWP on Windows Desktop once we get the final bits (it's looking good so far).
ArcGIS Runtime Quartz will have full support for UWP. There are currently no plans for full UWP support in the 10.2.x releases. As mentioned above you can get it working on desktop, but will definitely not work on mobile.