去图，经过一个小时左右的搜索，我去找到确切答案，30秒后我张贴我的问题。

Go figure, after an hour or so of searching, I go and find the exact answer 30 seconds after I post my question.

解决的办法是添加以下上下文类：

The solution was to add the following to the context class:

modelBuilder.Entity<Vendor>()
                .HasMany<Questionnaire>(x => x.OpenQuestionnaires)
                .WithMany(x => x.Vendors)
                .Map(x =>
                    {
                        x.MapLeftKey("vID");
                        x.MapRightKey("qID");
                        x.ToTable("VendorQuestionnaires");
                    });

我找到了答案通过阅读这个堆栈溢出职位：的 EF code首先许多到许多不工作