问题
I have just upgraded to Windows 8.1 and installed Visual Studio 2013. I am trying to update a previous WP7.1 solution but when opening with VS2013 I am asked to update some things. I select yes, and everything seems to work except for the Windows Phone Toolkit I got from NuGet in my original solution (built in VS2012). After updating I had a migration report error saying Some NuGet packages were installed using a target framework different from the current target framework and may need to be reinstalled. For more information, visit http://docs.nuget.org/docs/workflows/reinstalling-packages. Packages affected: WPtoolkit. Since my app was built targeting WP7.1 in VS2012 I assumed that removing and redownloading the WPToolkit would work, but it targets WP80 by default. It seems I cannot create a Windows Phone app targeting 7.1 anymore? Is there a solution for this?
回答1:
You can not create wp7.1 apps in vs2013. It is not supported by visual studio 2013.However you can upgrade your wp7 app to wp8 app in vs2013. just open it in vs2013 and do same manual changes
回答2:
Goto Tools>Nuget Package Manager> Package Manager Console
Write the following command:
PM> Update-Package -reinstall SilverlightToolKitWP
来源：https://stackoverflow.com/questions/19759876/how-to-target-wp7-1-in-visual-studio-2013