如何重置@html.列表框在 MVC 中使用 jquery 清空 Asp.net

Question

@Html.ListBox（"project type"， new SelectList（db.tblTypes.ToList（）， "ID"， "Name"）， new { multiple = "multiple"， id = "projectType" }）

这是我的 ajax 代码，我希望它为空

$（"#frm"）.submit（function （e） {

                e.preventDefault(e);
             //$('#frm').submit();
             var e = document.getElementById("myselect");
             var selectedIndices = [];
             $(function () {
                 $.each($('select[multiple]'), function (sIndex, sValue) {
                     if (sIndex == 0) {
                         $.each(this.options, function (oIndex, oValue) {
                             if (this.selected)
                                 selectedIndices.push(oIndex);
                         });
                     } else {
                         for (var i = 2; i < selectedIndices.length; i++) {
                             this.options[selectedIndices[i]].selected = true;
                         }
                     }
                 });
             });
             var project = {
                 ProjectTitle: $('#ProjectTitle').val(),
                 ProjectNumber: $('#ProjectNumber').val(),
                 Portfolio: $('#Portfolio').val(),
                 TotalSalesCC: $('#TotalSalesCC').val(),
                 grossMarginCC: $('#GrossMarginCC').val(),

                 projectMarginCC: $('#ProjectMarginCC').val(),
                 projectStatus: e.options[e.selectedIndex].value,
                 ImpStartDate: $('#ImpStartDate').val(),
                 ImpEndDate: $('#ImpEndDate').val(),
                 projectType: selectedIndices,
                 isSurvey:$('#hide').val()
             };
             if ($("#ProjectNumber").val() == "") {
                 $.growl.error({ message: 'Please fill  project number.' });
                 return false;
             }
             if ($("#ProjectTitle").val() == "") {
                 $.growl.error({ message: 'Please fill project title.' });
                 return false;
             }
             if (selectedIndices.length == 0 || selectedIndices.length < 1) {
                 $.growl.error({ message: 'Please choose atleast one project type.' });
                 return false;
             }

             var s=$("#ImpStartDate").val();
             var e = $("#ImpEndDate").val();
             if (s == "" )
             {
                 $.growl.error({ message: 'Please enter start date.' });
                 return false;
             }
             else if (e == "")
             {
                 $.growl.error({ message: 'Please enter end date.' });
                 return false;
             }
             else if (s > e) {
                 $.growl.error({ message: 'End date should be greater than start date.' });
                 return false;
             }
                 var date = new Date();
                 date.setDate(date.getDate()-1);
                 //$('#ImpStartDate').datepicker({
                 //    startDate: date
                 //});


             $.ajax({
                 type: "POST",
                 url: "/Projects/Create",
                 data: JSON.stringify(project),
                 contentType: "application/json; charset=utf-8",
                 success: function (s) {
                     console.log(s);
                     LoadProjectsGrid();
                     //LoadprojectsGrid();

                     // End For
                     $.growl.notice({ message: ' Your Project created successfuly' });
                     $("#projectType").html('');
                 },
                 failure: function (response) {
                     alert(response.d);
                 }
             });
                 // clear list via dom


                 // or clear list via jquery & dom




             $('#frm').find(".has-success").removeClass("has-success");
             $('#frm').find(".glyphicon-ok").removeClass("glyphicon-ok");
             $('.panel-collapse').collapse('hide');
             $('.panel-title').attr('data-toggle', 'collapse');
             document.getElementById('frm').reset();
             $('#accordion .ui-accordion-content ').hide();




         });

Answer 1

如果要

在客户端清空它，请使用

$("#projectType").html('');

如果你想在服务器端有一个空的值，请使用

$("#projectType").val('');