改成
Dim Book As New XLS.Book(ProjectPath & "Attachments\采购审批表集中采购.xlsx")
Dim fl As String = ProjectPath & "Reports\" & vars("aaaaa") & ".xlsx" '此语句为什么通不过呢,全局变量是aaaaa
Book.Build() '生成细节区
Book.Save(fl) '保存工作簿
Dim Proc As New Process '打开工作簿
Proc.File = fl
'proc.Verb = "Print" '指定动作
Proc.Start()