为什么下拉列表中没有选择选项？

Question

我很困惑为什么选择列表中的相应选项没有被选中。 当我单步执行循环时，item.DisciplineId = 2，但未选择学校（“选择”仍然是）。有什么建议吗？

查看

<% foreach (var item in Model.TeamMembers)
{ %>
<tr>
    <td>
        <%: Html.DropDownListFor(m => item.DisciplineId, Model.MemberDisciplines, "Choose") %>
    </td>
</tr>
<% } %>

查看模型

public SelectList MemberDisciplines { get; set; }
public IEnumerable<TeamMember> TeamMembers { get; set; }//Set from the model

MemberDisciplines = new SelectList(new[] {
                new SelectListItem{ Text = "Technical", Value = "1"},
                new SelectListItem{ Text = "School", Value = "2"},
                new SelectListItem{ Text = "Health", Value = "3"}
            }, "Value", "Text");

Answer 1

好的，那我建议你把 MemberDisciplines 属性转换成一个方法，内容如下：

public SelectList GetMemberDisciplines(object selectedValue)
{
    return new SelectList(new[] {
        new SelectListItem{ Text = "Technical", Value = "1"},
        new SelectListItem{ Text = "School", Value = "2"},
        new SelectListItem{ Text = "Health", Value = "3"}
    }, "Value", "Text", selectedValue);
}

然后你像这样在 DropDownListFor 中调用它：

<% for (int i = 0; i < Model.TeamMembers.Count; i++) { %>
  <tr>
      <td>
          <%: Html.DropDownListFor(m => Model.TeamMembers[i].DisciplineId, Model.GetMemberDisciplines(Model.TeamMembers[i].DisciplineId), "Choose..")%>
      </td>
  </tr>
<% } %>