I need to grab information between two instances of my WPF app (the contents of a public collection, to be precise). Any help?
You'll need to use some form of Interprocess Communication.
Since you're using WPF, and hence .NET, I'd recommend using Windows Communication Foundation. If these instances are running on the same system, using pipes via WCF is a great option.
Do you mean between two processes or app domains? I'd look up AppDomain and see if that works for your situation. If you need to communicate between two processes, I'd use named pipes through WCF.
来源：https://stackoverflow.com/questions/2484505/wpf-communicate-between-multiple-application-instances