Javascript MVC 4基于下拉列表更改多个显示字段以供选择

首先，与上述问题几乎相同，但解决方案不适用于此问题

我有一个网页，将举行一个下拉列表。选择后，它将根据选择更改显示字段

视图中的javascript是：

<script type="text/javascript">
    $(function(){
        $('#courseName').on('change', function () {
            var courseID = $(this).val();
            var studentID = '@ViewBag.StudentID';
            $.ajax({
                url: '@Url.Action("FillCourseInfo", "Student")',
                data: {StudentID: studentID, CourseID: courseID},
                type: 'get'
            }).done(function(data){
                $('#courseStartDate').text(data.courseStartDate); 
                $('#courseEndDate').text(data.courseEndDate);
                $('#projectName').text(data.projectName);
                $('#graduated').text(data.graduated);
            });
        });
    });

</script>

---

目前javascript没有被命中，或者我的方法没有被调用。

使用以下功能更改javascript函数：

$("#CourseName").change(function () {

            var courseID = $(this).val();
            $.ajax({
                type: 'POST',
                url: '@Url.Action("FillCourseInfo","Student")', // we are calling json method
                dataType: 'json',
                data: { StudentID: @ViewBag.studentID, CourseID, courseID  },


                success: function (ret) {
            $('#Dates').val(ret.courseDates); 
                    $('#Project').val(ret.projectName);
                    $('#Graduated').val(ret.graduated);

                },
                error: function (ex) {
                    //alert('Failed to retrieve states.' + ex);
                }
            });

            return false;
        });

使用以下功能更改控制器功能

public JsonResult FillCourseInfo(int StudentID, int CourseID)
{
     var ret = (from e in db.Enrollments 
               join c in db.Courses on e.CourseID equals c.CourseID
               where e.StudentID == StudentID && e.CourseID == CourseID
               select new StudentCourseDetails
               {
                   courseDates = c.CourseStartDate.ToString() + " " + c.CourseEndDate.ToString(),
                   projectName = e.Project.ProjectTitle,
                   graduated = e.Graduated

               });
    return Json(ret);
}

---

您正在做的一件事是不返回FillCourseInfo操作的单个结果

这意味着您的json结果是StudentCourseDetails的列表。您必须使用$'Dates'。valdata[0]。courseDates；获取你的价值观

或者，如果您只需要一个值，则可以在linq查询结束时使用.FirstOrDefault

var ret = (from e in db.Enrollments 
               join c in db.Courses on e.CourseID equals c.CourseID
               where e.StudentID == StudentID && e.CourseID == CourseID
               select new StudentCourseDetails
               {
                   courseDates = c.CourseStartDate.ToString() + " " + c.CourseEndDate.ToString(),
                   projectName = e.Project.ProjectTitle,
                   graduated = e.Graduated

               }).FirstOrDefault();

我为您创建了另一个.NET小提琴

要在linq查询中使用ToString，请将结果转换为列表，然后构建json

 var ret = (from e in db.Enrollments
                   join c in db.Courses on e.CourseID equals c.CourseID
                   where e.StudentID == StudentID && e.CourseID == CourseID
                   select new
                   {
                       courseStartDate = c.CourseStartDate,
                       courseEndDate = c.CourseEndDate,
                       projectName = e.Project.ProjectTitle,
                       graduated = e.Graduated

                   }).ToList()
                   .Select(a => new StudentCourseDetails() {
                       courseDates = a.courseStartDate.ToString() + " " + a.courseEndDate.ToString(),
                       projectName = a.projectName,
                       graduated = a.graduated
                   }).FirstOrDefault();

---

两个快速问题-jquery中呈现的url是什么？你能粘贴吗？还要设置contentType:'application/json'并试一试。处理错误事件并查看您得到的错误。如果下拉列表代码正确，则需要在JQuery选择器$'courseName'中使用相同的大小写。在'change'上，函数{如果你的字面意思是从$'CourseName'转到$'CourseName'，那么这不起作用，因为在你的linq查询中，你可以使用.toString，而我不能。这是因为在我的示例中，它是从列表中选择的，而不是从IEnumerableYeah中选择的。注意到了这一点。因此这些字段不需要编辑。我尝试使用DisplayFor但这不起作用，即使脚本正在运行，也不会出现任何问题。是否有我刚刚缺少的另一个可供使用的脚本？是否需要将值传递回控制器？否。严格来说，用于查看学生参加的课程的详细信息。因此，请选择一个课程并显示值。我的意思是，我可以禁用teXTbox，但我认为没有文本框的显示更干净

var ret = (from e in db.Enrollments 
               join c in db.Courses on e.CourseID equals c.CourseID
               where e.StudentID == StudentID && e.CourseID == CourseID
               select new StudentCourseDetails
               {
                   courseDates = c.CourseStartDate.ToString() + " " + c.CourseEndDate.ToString(),
                   projectName = e.Project.ProjectTitle,
                   graduated = e.Graduated

               }).FirstOrDefault();

 var ret = (from e in db.Enrollments
                   join c in db.Courses on e.CourseID equals c.CourseID
                   where e.StudentID == StudentID && e.CourseID == CourseID
                   select new
                   {
                       courseStartDate = c.CourseStartDate,
                       courseEndDate = c.CourseEndDate,
                       projectName = e.Project.ProjectTitle,
                       graduated = e.Graduated

                   }).ToList()
                   .Select(a => new StudentCourseDetails() {
                       courseDates = a.courseStartDate.ToString() + " " + a.courseEndDate.ToString(),
                       projectName = a.projectName,
                       graduated = a.graduated
                   }).FirstOrDefault();