我有一个问题，即所选值不适用于Html.DropDownList帮助器方法。见下文:这是我的Controller:publicActionResultEdit(intid=0){NewsEventitem=GetItem(id);ViewBag.NewsItemId=newSelectList(ViewBag.NewsItemId.Items,"Id","Name",item.NewsItemId);returnView(item);}这是我的观点:@Html.DropDownList("NewsItemId",ViewBag.NewsItemIdasSelectList,string

publicclassComboboxItem{publicstringText{get;set;}publicstringValue{get;set;}publicoverridestringToString(){returnText;}}privatevoidcomboBox1_SelectedIndexChanged(objectsender,EventArgse){intselectedIndex=comboBox1.SelectedIndex;intselecteVal=(int)comboBox1.SelectedValue;ComboboxItemselectedCar=

publicclassComboboxItem{publicstringText{get;set;}publicstringValue{get;set;}publicoverridestringToString(){returnText;}}privatevoidcomboBox1_SelectedIndexChanged(objectsender,EventArgse){intselectedIndex=comboBox1.SelectedIndex;intselecteVal=(int)comboBox1.SelectedValue;ComboboxItemselectedCar=

DropdownButtonValuedoesnotupdateevenafterselectingdifferentitems.如果默认值为空，则显示错误消息，如果我传递任何默认值(非空)，则它永远不会更改为其他选定值。currentCategory设置为DropdownButton的默认值。StreamBuilder(stream:Firestore.instance.collection('categories').snapshots(),builder:(BuildContextcontext,AsyncSnapshotsnapshot){currentCategory=sna

我有下拉列表，我从数据库中填充了它。现在我需要在Controller中获取选定的值进行一些操作。但没有得到这个想法。我试过的代码。型号publicclassMobileViewModel{publicListMobileList;publicSelectListVendor{get;set;}}ControllerpublicActionResultShowAllMobileDetails(){MobileViewModelMV=newMobileViewModel();MV.MobileList=db.Usp_InsertUpdateDelete(null,"","",null,""