部分视图不在mvc 5中打印值

Question

我使用ajax调用执行部分视图控制器操作以打印最大批号。一切都在执行，但值不会在局部视图中打印。在选定的下拉列表中，我调用ajax方法来执行。以下是我正在使用的代码。

Models.Batch.cs

[必需]

location /lite {
    alias /var/www/html/crm-lite/dist/;
}

BatchController.cs

    [StringLength(100)]
    [DataType(DataType.Text)]
    [Display(Name = "Batch Number")]
    public string BatchNumber { get; set; }

CreateBatch.cshtml

public PartialViewResult GetBatchNumber(string CourseID)
        {

            Context.Batches contBatch = new Context.Batches();
            Models.Batches b = new Models.Batches();
            b.BatchNumber = contBatch.GetallBatchList().ToList().Where(p => p.CourseId == CourseID).Select(p => p.BatchNumber).Max().FirstOrDefault().ToString();
            ViewBag.Message = b.BatchNumber;
            return PartialView(b);
        }

GetBatchNumber.cshtml

 <div class="col-md-10">
            @Html.DropDownListFor(m => m.CourseId, Model.Courses, new { id = "ddlCourse" })
            <div id="partialDiv">
                @{
                    Html.RenderPartial("GetBatchNumber", Model);
                }

            </div> 
            <script>
                $("#ddlCourse").on('change', function () {

                    var selValue = $('#ddlCourse').val();

                    $.ajax({
                        type: "GET",
                        url: '/Batch/GetBatchNumber?CourseId=' + selValue,
                        dataType: "json",
                        data: "",
                        success: function (data) {
                            $("#partialDiv").html(data);
                        },
                failure: function (data) {
                    alert('oops something went wrong');
                }
                });
                });
            </script>


            </div>