MyCompanyViewModel类不包含CVId属性的定义，因此默认情况下，Automapper不知道他应该带哪个位置用于注入Company的CVId属性的值.只需定义它即可:

MyCompanyViewModel class does not contain a definition of CVId property, so by default Automapper does not know where he should take a value for injecting into Company's CVId property. Just define it:

public class MyCompanyViewModel
{
    public int CVId { get; set; }
    // Other properties
}

然后为每个CompanyViewModel在视图中添加相应的隐藏输入字段:

Then for each CompanyViewModel add corresponding hidden input field into the view:

@for (int i = 0; i < Model.Companies.Count; i++)
{

    // ...

    @Html.HiddenFor(m => Model.Companies[i].CVId)

    // ...

}

你很好！