Question

我的控制器如下......

       public ActionResult Create()
    {

        ViewBag.Dept = (DbStudent.StudentDetails.Select(s => s.StudDept)).Distinct();
        return View();
    } 

    //
    // POST: /Student/Create

    [HttpPost]
    public ActionResult Create(StudentDetail studentdetail)
    {
        try
        {
            // TODO: Add insert logic here I used Stored procedure for it
            var query = DbStudent.StudInsert(studentdetail.StudName,
                                          studentdetail.StudDept, 
                           studentdetail.Mark1, studentdetail.Mark2);

            return RedirectToAction("Index");
        }

在视图中，我包含以下内容

  <div class="editor-field">
     @Html.DropDownListFor(model => model.StudDept, new SelectList(ViewBag.Dept as                       System.Collections.IEnumerable), 
       "Select Any Department")
  </div>

DropDown得到填充，但选择下拉列表时我只得到空值。请帮我。我不知道我做错了什么

提前致谢

此致苏里亚

Answer 1

假设StudDept是StudentDetail对象的外键（因此您希望将所选值设置为StudDeptId）。这应该为您定义的集合的下拉列表，空字符串的值，标签和默认值。

试试这个：

<%= Html.DropDownListFor(model => model.StudDeptId, 
                              new SelectList(ViewBag.Dept, 
                                             "id", 
                                             "Name", 
                                             ""))%>

Answer 2

我在StudentModel中创建了一个getDept属性，然后使用它填充了Drodownlist。然后使用Jquery我传递了Value it。这是代码。

  public partial class StudentDetail
{   
    private string _StudName;
    private string _StudDept;
    private System.Nullable<int> _Mark1;
    private System.Nullable<int> _Mark2;
    private int _StudID;
    public StudentDetail()
    {
    }
    public IEnumerable<SelectListItem> getDept
    {
        get
        {
            StudentClassesDataContext objStud = new StudentClassesDataContext();
            var Dept = objStud.StudentDetails.Select(x => x.StudDept).Distinct();
            var deptlist = Dept.AsEnumerable();

            return deptlist.Select(x => new SelectListItem
            {
                Value = x.ToString(),
                Text = x.ToString()
            });

        }

    }....

在控制器中我包含了以下内容..

 public ActionResult studentName(string Dept)
    {
        var result = from s in DbStudent.StudentDetails where s.StudDept == Dept                                         orderby s.StudName select s.StudName;
        var Studname = result.AsEnumerable().Select(x => new { value = x.ToString(),  text = x.ToString() });
        return Json(Studname,JsonRequestBehavior.AllowGet);
    }

And In View ..

  <div>
  Search for Another Student<br />
    Department
     @Html.DropDownListFor(x => x.StudDept,new SelectList(Model.getDept, "Value",     "Text"),"--Select Any Dept --")
  Student Name
  @Html.DropDownListFor(x => x.StudName, Enumerable.Empty<SelectListItem>(), "--Select   Any Student--")

     <script type="text/javascript">
$('#StudDept').change(function () {
    var selectedDept = $(this).val();
    if (selectedDept != null && selectedDept != '') {
        $.getJSON('@Url.Action("studentName")', { Dept: selectedDept }, function (names) {
            var nameSelect = $('#StudName');
            nameSelect.empty();
            $.each(names, function (index, name) {
                nameSelect.append($('<option/>', {
                    value: name.value,
                    text: name.text
                }));
            });
        });
    }
});
     $('#StudName').change(function () {
    var Dept = $('#StudDept').val();
    var Name = $('#StudName').val();
    window.location = "/Student/Search/" + Name ;
    //alert("Selected Name is " + Name + " And Selected Dept is " + Dept);
});
  </script>

最后，我从Dropdownlist中获得了Selected值。希望它对别人有用...... 感谢

在MVC 3中的DropDownList中选择时取空值

2 个答案: