MVC3 选定值

Question

在我的模型中：

public SelectList QuestionGroupSelectList { get; set; }

------
List<QuestionGroup> questionGroupList = questionGroupRepository.GetQuestionGroup_BySurveyId(survey.Id);

Dictionary<int, string> questionGroupDictionary = questionGroupList.ToDictionary(l => l.Id, l => l.Name);

QuestionGroupSelectList = new SelectList(questionGroupDictionary, "key", "value", questionGroupId);





---------------------------------------
In view:
@Html.DropDownList("QuestionGroupSelectList", Model.QuestionGroupSelectList, "Choose Here")

当我调试时，我在 QuestionGroupSelectList 中得到 2 项（一项 Id 30，一项 Id 35），它说 selectedValue 是 35 (questionGroupId = 35)

但 selectedvalue 在视图中不起作用，任何想法？

提前致谢！

Answer 1

您应该使用不同的属性来绑定下拉列表值。此外，您还应该使用视图模型和强类型助手，如下所示：

public class MyViewModel
{
    public int QuestionGroupId { get; set; }
    public SelectList QuestionGroupSelectList { get; set; }
}

然后您可以有一个控制器操作来填充此视图模型并将其传递给视图：

public ActionResult Foo()
{ 
    // This collection could come from anywhere 
    // normally you will query a repository here to fetch those values
    var values = new[] 
    {
        new { Key = "1", Value = "item 1" },
        new { Key = "2", Value = "item 2" },
        new { Key = "3", Value = "item 3" },
    }

    var model = new MyViewModel
    {
        // preselect the second value
        QuestionGroupId = 2,
        QuestionGroupSelectList = new SelectList(values, "Key", "Value")
    }
    return View(model);
}

最后在您的视图中：

@model MyViewModel

@Html.DropDownListFor(
    x => x.QuestionGroupId, 
    Model.QuestionGroupSelectList, 
    "Choose Here"
)