I have an EF4 EDM called
context = new UnitHistoryEntities()
var unit = new Unit()
Turns out the problem I'm having is very similar to this question. I have a DateTime field that I was not setting. I made a console app that performed exactly the same actions on the context that my application was doing. In this case,
SaveChanges() did return, with the exception
The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value.\r\nThe statement has been terminated.
So I now set my DateTime field to 1/1/1900 and I'll treat that like a null date. My program now operates properly.
Strange that I didn't get an exception thrown in my WPF application, but I did in the console application...