DataGridViewComboBoxCell不显示任何内容

Question

我有一个dataGridView，其中有许多列，所有列都由dataPropertyName绑定到dataSource。

datagridviewcombobox应该显示项目列表（这些项目具有多个属性，一个ID属性和一个Name属性，这些属性也存储在数据网格的数据源中。

根据我为每个datagridviewbombobox单元格设置的值，我希望显示属性的匹配名称。

一切正常，所有datagridviewcomboboxcells中的值都是正确的，我设置了display和value成员。那么为什么datagridviewcombobox不显示任何内容？

我查看了发现的大多数线程，但找不到解决方法。

预先感谢您的帮助。

       List<ProcessGroup> processGroups = _context.ProcessGroup.ToList();

        _ds = new List<TestRessourceDetailsModel>();

        for (int i = 0; i < processGroups.Count; i++)
        {
            List<IntrusionBody> ibs = null;
            int? id = _curTestRes.TestResourceProcessGroup.OrderBy(x => x.ProcessGroupID).Where(y => y.ProcessGroupID == i + 1).FirstOrDefault()?.ID;
            if (_view.Cb_Location.SelectedItem != null)
            {
                if (_curTestRes != null)
                {
                    ibs = _context.IntrusionBody.Where(x => x.ProcessGroupID == i + 1 && x.ToDate == null && (x.TestRessourceProcessGroupID == null || x.TestRessourceProcessGroupID == id)).ToList();
                }
                else
                {
                    ibs = _context.IntrusionBody.Where(x => x.ProcessGroupID == i + 1 && ((Location)_view.Cb_Location.SelectedItem).ID == x.LocationID && x.ToDate == null && x.TestRessourceProcessGroupID == null).ToList();
                }
            }
            else
            {
                    ibs = _context.IntrusionBody.Where(x => x.ProcessGroupID == i + 1 && x.ToDate == null && x.TestRessourceProcessGroupID == null || x.TestRessourceProcessGroupID == id).ToList();
            }

            _ds.Add(new TestRessourceDetailsModel
            {
                ProcessGroup = processGroups[i].Name,
                E_DIN = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "E (DIN)").FirstOrDefault()?.Activated,
                E_U_DIN = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "E+U (DIN)").FirstOrDefault()?.Activated,
                R_DIN = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "R (DIN)").FirstOrDefault()?.Activated,
                E_REF_DIN = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "E (Ref. DIN)").FirstOrDefault()?.Activated,
                E_ASTM = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "E (ASTM)").FirstOrDefault()?.Activated,
                E_U_ASTM = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "E+U (ASTM)").FirstOrDefault()?.Activated,
                R_ASTM = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "R (ASTM)").FirstOrDefault()?.Activated,
                E_REF_ASTM = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestOptionTestRessourceProcessGroup.Where(x => x.TestOption.Name == "E (Ref. ASTM)").FirstOrDefault()?.Activated,
                NrOfImpressions = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.NrOfImpressions,
                TestsPerDay = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.NrOfTestPerDay,
                IntrusionBody = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.IntrusionBody.Where(x => x.ToDate == null).FirstOrDefault(),
                IntrusionBodies = ibs,
                DINLocked = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.DINLocked,
                ASTMLocked = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.ASTMLocked,
                Active = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.Active,
                IsCertifiedDin = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestResourceProcessGroupCertification.Where(x => x.Date.Year == DateTime.Now.Year).FirstOrDefault()?.DIN,
                IsCertifiedAstm = processGroups[i].TestResourceProcessGroup.Where(x => x.TestResourceID == _curTestRes?.ID).FirstOrDefault()?.TestResourceProcessGroupCertification.Where(x => x.Date.Year == DateTime.Now.Year).FirstOrDefault()?.ASTM
            });

        }

        _view.Dgv_ProcessGroups.AutoGenerateColumns = false;
        _view.Dgv_ProcessGroups.DataSource = _ds;




        ((DataGridViewCheckBoxColumn)_view.Dgv_ProcessGroups.Columns[13]).ThreeState = true;
        ((DataGridViewCheckBoxColumn)_view.Dgv_ProcessGroups.Columns[14]).ThreeState = true;


        foreach (DataGridViewRow row in _view.Dgv_ProcessGroups.Rows)
        {
            ((TestRessourceDetailsModel)row.DataBoundItem).IntrusionBodies.Insert(0, new IntrusionBody { ID = 999999, Name = "" });

            ((DataGridViewComboBoxCell)row.Cells[12]).DataSource = ((TestRessourceDetailsModel)row.DataBoundItem).IntrusionBodies;

            ((DataGridViewComboBoxCell)row.Cells[12]).DisplayMember = "Name";
            ((DataGridViewComboBoxCell)row.Cells[12]).ValueMember = "ID";

            if (((TestRessourceDetailsModel)row.DataBoundItem).IntrusionBody != null)
            {
                ((DataGridViewComboBoxCell)row.Cells[12]).Value = ((TestRessourceDetailsModel)row.DataBoundItem).IntrusionBody?.ID;
            }
            else if (((TestRessourceDetailsModel)row.DataBoundItem).IntrusionBodies.Count > 0)
            {
                ((DataGridViewComboBoxCell)row.Cells[12]).Value = ((TestRessourceDetailsModel)row.DataBoundItem).IntrusionBodies.First().ID;
            }
        }