Question

我的观点是呈现为文本框，下拉列表和复选框的问题集合。这些问题存储在数据库中。

对于我的观点，我创建了一个viewmodel

public class SpecialProgram
{
    public string Role { get; set; }

    public List<QuestionAnswer> QuestionAnswerList { get; set; }

    // other prop
}  

public class QuestionAnswer
{
    // other prop

    public int QuestionID { get; set; }

    public string Question { get; set; }

    public string ControlType { get; set; }

    public int QuestionSortOrder { get; set; }

    public string Answer { get; set; }

    public IEnumerable<SelectListItem> DataList { get; set; }
}

现在这是我的观点

@model MyApplication.SpecialProgram

@using (Html.BeginForm("SavePage", "MyController", FormMethod.Post, new { enctype = "multipart/form-data", @id = "formData" }))
{
    @for (int i = 0; i < Model.QuestionAnswerList.Count(); i++)
    {
        // other stuff......

        else if (@Model.QuestionAnswerList[i].ControlType == "DropDown")
        {
           <div class="col-lg-12">
              <div class="input-group" style="padding: .15em .15em .15em .15em">
                 <span class="input-group-addon" style="width:350px; text-align: left;">@Model.QuestionAnswerList[i].Question</span>
                @Html.DropDownListFor(mod => mod.QuestionAnswerList[i].Answer, Model.QuestionAnswerList[i].DataList, "--Select--", new { @class = "form-control placeholder-color answers", style = "width: 150px;" })
             </div>
         </div>
      }
   }
}

现在让我们说我的数据列表是一个是和否列表。这是我如何从数据库中获取我的值并将我的值传递给View

public List<QuestionAnswer> MYMethod()
{
     List<QuestionAnswer> qadata = new List<QuestionAnswer>();

     List<SelectListItem> YesNoList = new List<SelectListItem>();
     YesNoList.Add( new SelectListItem { Text = "Yes", Value = "1" });
     YesNoList.Add( new SelectListItem { Text = "No", Value = "0" });         

     qa.DataList = YesNoList;

     // the qa.Answer here is 1. which is the selected dropdown value saved in db. I want yes to be pre-selected on page load. But for some reason On page load I get default value "--Select--"


}

仅出于测试目的，我尝试将值设置为下拉列表。这工作

var data = '@Model.QuestionAnswerList[2].Answer';
$('#ddlMYddl').val(data)

但是使用jquery并没有真正解决我的问题。我想@ Html.DropDownListFor工作

@Html.DropDownListFor(mod => mod.QuestionAnswerList[i].Answer, Model.QuestionAnswerList[i].DataList, "--Select--", new { @class = "form-control placeholder-color answers", style = "width: 150px;" })

总结一下。使用上面的代码呈现的下拉列表有3个选择选项（yes，no， - select--）。基于来自DB的页面加载答案ddlMYddl应选择“是”但我得到 - 选择 -

我哪里出错

Answer 1

当您在MYMethod时，您知道在创建列表时选择了哪个？如果是这样，您可以使用selected的{{1}}属性并将其设置为true。

SelectedListItem

将值设置为动态HTML DropDownListFor MVC5的问题

1 个答案: