如何在复杂对象中实例化相同类型的列表？

Question

这是我遇到的一个棘手的情况。我知道这是一个简单的，但我猜我错过了。

有复杂的类型对象..

ini_set('xdebug.max_nesting_level', 200);

ListGroupMembershipUploadInput看起来像

public class GroupMembershipValidationOutput
{
    public ListGroupMembershipUploadInput GroupMembershipInvalidList { get; set; }
    public ListGroupMembershipUploadInput GroupMembershipValidList { get; set; }

 ...................... // other defs
}

现在有一个父对象列表（也是同一类型），我将分别解析有效列表和无效列表。

public class ListGroupMembershipUploadInput
{
    public List<GroupMembershipUploadInput> GroupMembershipUploadInputList { get; set; }
}

我试过

        GroupMembershipValidationOutput gmvo = new GroupMembershipValidationOutput();

        ListGroupMembershipUploadInput lgl = new ListGroupMembershipUploadInput();

        if (gmvo._invalidChapterCodes.Count != 0 || gmvo._invalidGroupCodes.Count != 0 || gmvo._invalidMasterIds.Count != 0)
        {
            lgl.GroupMembershipUploadInputList = new List<GroupMembershipUploadInput>();
            var result = mainCollection.GroupMembershipUploadInputList
                            .Where(x => gmvo._invalidMasterIds.Select(y => y).Contains(x.cnst_mstr_id) ||
                                        gmvo._invalidChapterCodes.Select(y => y).Contains(x.chpt_cd) || 
                                        gmvo._invalidGroupCodes.Select(y => y).Contains(x.grp_cd)).ToList();

            if (result.Count > 0) //Means there are some invalid items
            {
                lgl.GroupMembershipUploadInputList = result; //Construct the invalid listfrom result
                gmvo.GroupMembershipInvalidList = lgl;

                ......... // How to construct the valid list

            }

但它为GroupMembershipValidList指定了null ..它不会使计数为0.。

如何解决？或者它是预期的？