Question

我正在学习EF Core和LINQ中的多对多联合表。我有以下模型：

    public class ProjectManager
    {
        public int ProjectID { get; set; }
        public Project Project { get; set; }

        public string AppUserID { get; set; }
        public AppUser AppUser { get; set; }
    }

我有以下ViewModel：

    public class DeleteUserFromProjectViewModel
    {
        public IQueryable<AppUser> Users { get; set; }
        public PagingInfo PagingInfo { get; set; }
    }

在我的控制器中，我尝试为ViewModel填充Users：

                DeleteUserFromProjectViewModel model = new DeleteUserFromProjectViewModel
                {
                    //HOW DO I RETURN JUST THE APPUSERS FROM THE PROJECT MANAGER OBJECT?
                    //Users = repository.ProjectManagers.Any(p => p.ProjectID == projectId).Select;

                    PagingInfo = new PagingInfo
                    {
                        CurrentPage = page,
                        ItemsPerPage = PageSize,
                        TotalItems = proj.ProjectManagers.Count()
                    }

                };

我尝试过kludge

                List<AppUser> userList = new List<AppUser>();
                foreach(ProjectManager pm in proj.ProjectManagers)
                {
                    //this gives error that cannot convert string userId to char??
                    foreach (string userId in pm.AppUserID)
                    {
                        AppUser newUser = await userManager.FindByIdAsync(userId);
                        userList.Add(newUser);
                    }
                }

Answer 1

因为您的pm.AppUserID已经是一个字符串值，所以如果在其上使用foreach，则将迭代字符串值，那么您将得到char

根据您的评论，您似乎可以使用linq Select。

List<AppUser> userList = proj.ProjectManagers.Select(x=>x.AppUser).ToList();

使用LINQ返回子对象

1 个答案: