Question

我想要做的是首先我需要显示我需要添加到组中的成员列表。然后，用户将单击用户选择的每行成员的每个复选框。我的代码已经运行了。问题是，当我应用jquery.dataTable（也完全呈现）时，当某些成员被隐藏（通过下一页或搜索）时，它似乎不会返回所有必要的数据。当我点击show 100，显示dataTable的每个隐藏数据时，一切正常。

我的ViewModel

public class ChooseMembersEditorViewModel
{
    public bool Selected { get; set; }
    public string Id { get; set; }
    public string Name { get; set; }
    public string Sex { get; set; }
    public string Age { get; set; }

    public ChooseMembersEditorViewModel()
    {
        this.Selected = false;
        this.Id = "";
    }
}

位于另一个ViewModel

中

public class AddMemberViewModel
{
    public List<Group> Group{ get; set; }
    public List<ChooseMembersEditorViewModel> LGMembers { get; set; }

    public AddLifegroupMemberViewModel()
    {
        this.Group= new List<Group>();
        this.LGMembers = new List<ChooseMembersEditorViewModel>();
    }

    public IEnumerable<string> getSelectedIds()
    {
        var getSelected = (from members in this.LGMembers
                           where members.Selected
                           select members.Id); //returns error here saying value cannot be null
        System.Diagnostics.Debug.WriteLine(string.Format("Count {0}", getSelected.Count()));
        return getSelected;
    }
}

Screenshot

当我检查其中一个值并点击Add Member时，我从getSelectedIds Linq中获取的值不能为null

提前谢谢！

修改

这是我列出所有成员的方式。 SubmitSelectedMembers基本上会获取其ID已被检查的所有成员，并将其添加到数据库中。

[Authorize(Roles = "Admin")]
    public ActionResult AddLifegroupMembers(int id)
    {
        var model = new AddLifegroupMemberViewModel();

        Lifegroup lifegroup = db.Lifegroup.Find(id);

        int leaderAge = GetAge(lifegroup.LGLeader.User.Birthday);
        ViewBag.Age = leaderAge;

        System.Diagnostics.Debug.WriteLine(string.Format("{0}", lifegroup.LGName.ToString()));

        var nonMembers = from u in db.Users
                         where !(from lgm in db.LGMember
                                 select lgm.UserID).Contains(u.Id) //should not be part of any Lifegroup
                                 &&
                               !(from l in db.Lifegroup
                                 where l.LifegroupID.Equals(id)
                                 select l.LGLeader.UserID).Contains(u.Id) //should not include leader of said group
                         select u;

        System.Diagnostics.Debug.WriteLine(string.Format("Number of LG: {0}", model.Lifegroup.Count()));

        foreach (var user in nonMembers)
        {
            int age = GetAge(user.Birthday);

            var editorViewModel = new ChooseMembersEditorViewModel()
            {
                Id = user.Id,
                Name = string.Format("{0} {1}", user.FirstName, user.LastName),
                Selected = false,
                Age = age.ToString(),
                Sex = user.Sex
            };

            model.LGMembers.Add(editorViewModel);
        }
        model.Lifegroup.Add(lifegroup);

        return View(model);
    }

    public ActionResult SubmitSelectedMembers(AddLifegroupMemberViewModel model)
    {
        var getSelected = (from members in model.LGMembers
                           where members.Selected
                           select members.Id);

        List<string> _selected = new List<string>();
        foreach (var selected in getSelected)
        {
            _selected.Add(selected);
        }

        //var selectedIds = model.getSelectedIds();
        var lifegroupID = model.Lifegroup[0].LifegroupID;

        //System.Diagnostics.Debug.WriteLine(string.Format("Lifegroup ID: {0}", model.Lifegroup.LifegroupID));

        var selectedUsers = from u in db.Users
                            //where selectedIds.Contains(u.Id
                            where _selected.Contains(u.Id)
                            select u;

        foreach (var users in selectedUsers)
        {
            var idManager = new IdentityManager();
            idManager.AddUserToRole(users.Id, "LifegroupMember");

            var lgmember = new LGMember()
            {
                LifegroupID = lifegroupID,
                UserID = users.Id,
                DateJoined = DateTime.Now
            };

            /* 
             *  Insert Code to insert part of Lifegroup to GrowthMileStone                
             */

            db.LGMember.Add(lgmember);
        }
        db.SaveChanges();

        return RedirectToAction("ViewLifegroups");
    }

Answer 1

在将对象插入LGMembers列表之前，需要实例化对象。这不会发生在上面的代码中。

Answer 2

复选框输入null ViewModel的原因是，过滤或分页会将绑定视图切割为ViewModel。因为绑定无法看到发布时未显示的元素。虽然不是很好的解决方案，如果有人想以这种方式解决问题，解决这个问题的方法可能是在提交前删除过滤或分页。解决方案的示例放在表单提交

中

table.search('').columns().search('').draw()

或

table.fnFilter("");
var oSettings = table.fnSettings();
table._iDisplayLength = -1;
table.fnDraw();

MVC 4和dataTables：复选框条目返回null ViewModel

2 个答案: