如何提取表达细节？

Question

我具有以下方法签名：

 Public Function Method2(Of U)(ByVal aliasName As String, ByVal exp As Expression(Of Func(Of T, U, Boolean))) As Join

如果被称为：

.Method2(Of RelationPersonAddress)("Rel_adr", Function(x, y) x.PersonId = y.PersonId)

如何提取x.PersonId和y.PersonId？