C# each（）在控制器中设置视图时循环。即使手动设置每个列表中相关项目的。Selected属性也不会转换为视图本身。我已经更新了原始问题中的foreach（）代码，以显示新代码。我将在这里补充一点，在调试中单步执行代码可以完成“预期”的所有操作，这甚至不应该

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each（）在控制器中设置视图时循环。即使手动设置每个列表中相关项目的

。Selected

属性也不会转换为视图本身。我已经更新了原始问题中的

foreach（）

代码，以显示新代码。我将在这里补充一点，在调试中单步执行代码可以完成“预期”的所有操作，这甚至不应该是必需的。我怀疑问题可能是属性名

MemberTypeLookUp\u ID

中有下划线。试着去掉下划线，看看它是否有效。不，恐怕不行。我想你可能已经搞定了，因为我们的代码可能违反了一些奇怪的规则，但结果是一样的。我可以看到下划线现在已被删除的视图源（即：

id=“members\u 0\u\u MemberTypeLookUpID”name=“members[0]。MemberTypeLookUpID”

），但所有下拉列表仍然没有选择值。令人费解的。。。

    [Display(Name = "Team Member")]
    public int Contact_ID { get; set; }
    [Display(Name = "Team Member")]
    public String Contact_Name { get; set; }

    [Display(Name = "Type/Role")]
    public int MemberTypeLookUp_ID { get; set; }
    [Display(Name = "Type/Role")]
    public String MemberTypeValue { get; set; }
    [Display(Name = "Type/Role")]
    public LookUpList MemberTypeLookUp { get; set; }

    foreach (TeamEditViewItem tevi in this.members)
    {
        tevi.MemberTypeLookUp = new LookUpList("TeamMemberType");

        foreach (SelectListItem item in tevi.MemberTypeLookUp.list)
        {
            if (item.Value == tevi.MemberTypeLookUp_ID.ToString())
            {
                item.Selected = true;
                break;
            }
        }
    }

public class LookUpList 
{
    public SelectList list;

    // Return all Active LookUp entries for the passed-in Category.
    public LookUpList(String Category)
    {
        WorkpointContext _db = new WorkpointContext();

        int Customer_ID = _db.GetCustomer_ID();

        IList<LookUp> items = (from lookup in _db.LookUp
                                where (lookup.Category == Category)
                                && (lookup.IsActive == true)
                                orderby lookup.DisplayOrder ascending
                                select lookup).ToList();

        this.list = new SelectList(items, "ID", "Value");
    }

}

    @Html.DropDownListFor(model => model.members[i].MemberTypeLookUp_ID, Model.members[i].MemberTypeLookUp.list, "--Select--")
    @Html.ValidationMessageFor(model => model.members[i].MemberTypeLookUp_ID)

@model WebWorkPoint.Models.TeamEditView
<h3>Edit Team</h3>
@using (Html.BeginForm()) {
    <fieldset>
        @if (Model.members.Count>0)
        {
            <table>
            <!-- table headings -->
            <thead>
            <tr>
                <td style="text-align:center; border-bottom: 1px solid black; " >
                    <div class='editor-label'>
                        @Html.LabelFor(m => m.members.First().Contact_Name)
                    </div>
                </td>
                <td class="spacer-border"> </td>
                <td style="text-align:center; border-bottom: 1px solid black; " >
                    <div class='editor-label'>
                        @Html.LabelFor(m => m.members.First().MemberTypeValue)
                    </div>
                </td>
            </tr>
            </thead>

            <!-- table rows -->
            <tbody>
                @for (int i = 0; i < Model.members.Count; i++)
                {
                    <tr>
                        <td style="text-align:center; " >
                            @Html.HiddenFor(m => m.members[i].Contact_ID)
                            <div class="editor-field">
                                @Html.EditorFor(m => m.members[i].Contact_Name)
                                @Html.ValidationMessageFor(model => model.members[i].Contact_Name)
                            </div>
                        </td>
                        <td class="spacer"></td>
                        <td style="text-align:center; " >
                            <div class="editor-field">
                                @Html.DropDownListFor(model => model.members[i].MemberTypeLookUp_ID, Model.members[i].MemberTypeLookUp.list, "--Select--")
                                @Html.ValidationMessageFor(model => model.members[i].MemberTypeLookUp_ID)
                            </div>
                        </td>
                    </tr>
                }
            </table>
        }
        else
        {
            <p>There are currently no team members defined.</p>
        }
        <p>
            <input type="submit" value="Update Team" />
            @{
                sAction = "/" + Model.TableNameValue + "/" + Model.TableNameValue + "Show/" + Model.TableRecord_ID.ToString();
                sLinkText = "Cancel";
            }
            <button type="button" onclick="location.href='@sAction'" >@sLinkText</button>
        </p>
    </fieldset>
}

// other code above ...
foreach (TeamEditViewItem tevi in this.members)
{
    tevi.MemberTypeLookUp = new LookUpList("TeamMemberType");
}

@Html.DropDownListFor(model => model.members[i].MemberTypeLookUp_ID, new SelectList(Model.members[i].MemberTypeLookUp.list, "Value", "Text", Model.members[i].MemberTypeLookUp_ID), "--Select--")