Javascript 从MVC中的下拉列表选择填充文本框

在从dropdownlist中选择一个选项后，我试图从jquery中填充一个文本框。我包含了一些代码片段

这是视图的标记

<div class="form-group">
        @Html.LabelFor(model => model.DependantID, "DependantID", htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.DropDownList("DependantID", null, htmlAttributes: new { @class = "form-control", @onchange = "GetRegNo()" })
            @Html.ValidationMessageFor(model => model.DependantID, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.RegNo, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @*@Html.EditorFor(model => model.RegNo, new { htmlAttributes = new { @class = "form-control" } })*@
            <span id="loading_progress1" style="display: none;">Please wait...</span>
            @Html.TextBoxFor(model => model.RegNo, new { @Value = @ViewBag.Regno, @readonly = "readonly", @class = "form-control" })
            @*@Html.TextBoxFor(model => model.RegNo, new { @Value = Regno, @readonly = "readonly", @class = "form-control" })*@
            @Html.ValidationMessageFor(model => model.RegNo, "", new { @class = "text-danger" })
        </div>
    </div>

---

因此，从我上面的代码片段来看，当dropdownlist中发生更改时，会调用java，java反过来调用控制器中的方法并填充文本框。如果有更好的办法，我完全愿意。谢谢。

我发现jquery脚本存在问题。我将张贴更改并指向更改。这和我的作业有关。我在这里标记的行将值发布到文本框中

function GetRegNo() {
    var dependid = $('#DependantID').val();
    var dprogress = $('#loading_progress1');
    dprogress.show();
    //alert(schoolid);
    $.ajax({
        cache: false,
        //url: '@Url.Action("/Patients/FillClass")',
        url: '/Patients/FillClass',
        type: "GET",
        datatype: "json",
        data: { DependID: dependid },
        success: function (stud) {
            $("#RegNo").html("");  ///clear entry before appending
     here:  $('input#RegNo').val(stud); //i missed it here, changing to this changed solved the problem, compare with with script in the question

        dprogress.hide();
        },
        error: function (response) {
        alert("Error: " + response.responseText);
        dprogress.hide();
        }

     });
   }

---

你发了一堆代码。它不起作用吗？您的问题中没有明确的问题状态。另外，你不应该把“JavaScript”称为“Java”，因为它们完全不同。谢谢你对Java和JavaScript的更正，我的错。但是我发布代码是为了让人们看到我正在努力实现的目标。不，它不起作用！同样，您没有在问题中提供明确的问题陈述。我不知道“不工作”是什么意思。你需要具体地描述什么是不起作用的。我想执行一种级联下拉列表，但不是填充另一个下拉列表，而是填充一个文本框。希望这能解释我想要实现的目标？

[AcceptVerbs(HttpVerbs.Get)]
    public ActionResult FillClass(int? dependid)
    {
        if (dependid == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        string regno="";
        var N = db.Patients.Max(f => (int?)f.PatientID).GetValueOrDefault(0);
        N++;
        string Nt = Convert.ToString(N);
        if (dependid == 1)
        {

           regno = "M" + Convert.ToString((DateTime.Now).ToString("yy")) + BizLogic.Right("00000" + Nt, 5);
        }
        else
        {

            regno = "D" + Convert.ToString((DateTime.Now).ToString("yy")) + BizLogic.Right("00000" + Nt, 5);
        }
        return Json(regno, JsonRequestBehavior.AllowGet);
    }

function GetRegNo() {
    var dependid = $('#DependantID').val();
    var dprogress = $('#loading_progress1');
    dprogress.show();
    //alert(schoolid);
    $.ajax({
        cache: false,
        //url: '@Url.Action("/Patients/FillClass")',
        url: '/Patients/FillClass',
        type: "GET",
        datatype: "json",
        data: { DependID: dependid },
        success: function (stud) {
            $("#RegNo").html("");  ///clear entry before appending
     here:  $('input#RegNo').val(stud); //i missed it here, changing to this changed solved the problem, compare with with script in the question

        dprogress.hide();
        },
        error: function (response) {
        alert("Error: " + response.responseText);
        dprogress.hide();
        }

     });
   }