Question

我有一个表将一个True / False值存储为sqlserver位字段（Featured）。首先，有没有比手动更好的方法为此生成下拉列表？

其次，这是我迄今为止所做的工作但不会将selected="selected"添加到DDL中的任何项目。

编辑1：我已根据建议的答案更新了此示例，并导致运行时错误:( 编辑2：像功能一样使用它（使用和不使用强制转换）但仍然没有添加所选=“已选择”。

型号：

//
// View models
public class SpotlightFormViewModel
{

    // props
    public Spotlight Spotlight { get; private set; }
    public SelectList FeaturedMenu { get; private set; }

    static IDictionary<string, int> feature = new Dictionary<string, int>(){
        {"True", 1},
        {"False", 0},
    };

    public IEnumerable<SelectListItem> FeaturedChoices(Spotlight spotlight)
    {
        return feature.Select(f => new SelectListItem
        {
            Text = f.Key,
            Value = f.Value.ToString(),
            Selected = spotlight.Featured,
        });
    }

    // constr
    public SpotlightFormViewModel(Spotlight spotlight)
    {
        Spotlight = spotlight;
        FeaturedMenu = new SelectList(FeaturedChoices(spotlight));
    }
}

控制器：

    public ActionResult Edit(int id)
    {
        Spotlight spotlight = spotlightRepository.GetSpotlight(id);

        return View(new SpotlightFormViewModel(spotlight));
    }

查看：

        <div class="editor-label">
            <%: Html.LabelFor(model => model.Spotlight.Featured) %>
        </div>
        <div class="editor-field">
            <%: Html.DropDownListFor(model => model.FeaturedMenu, Model.FeaturedChoices(Model.Spotlight))%>
            <%: Html.ValidationMessageFor(model => model.Spotlight.Featured) %>
        </div>

Answer 1

我使用与您相同的dropdowlist。但在你的情况下你可以简单地使用一些单选按钮：

 <%: Html.Label("True") %>
 <%: Html.RadioButtonFor(model => model.FeaturedMenu, "1") %>

 <%: Html.Label("False") %>
 <%: Html.RadioButtonFor(model => model.FeaturedMenu, "0") %>

其次，您谈到了“选定”值，但您没有在“公共IEnumerable FeaturedChoices”中使用它，您可以像这样添加所选值：

return feature.Select(f => new SelectListItem
{
    Text = f.Key,
    Value = f.Value.ToString(),
    Selected = false
});

Answer 2

我终于有了这个工作。即使我的语法＆amp;当我将变量传递给public IEnumerable FeaturedChoices(Spotlight spotlight)时，逻辑是正确的，即使我明确标记Selected = true，它也无法工作。如果有人能回答为什么会这样，我会很感激

正确应用selected="selected"的唯一方法是，如果我使用getter创建了FeaturedChoices属性。完整的工作代码

查看型号：

//
// View models
public class SpotlightFormViewModel
{

    // props
    public Spotlight Spotlight { get; private set; }
    public SelectList FeaturedMenu { get; private set; }

    static IDictionary<string, int> feature = new Dictionary<string, int>(){
        {"True", 1},
        {"False", 0},
    };

    public IEnumerable<SelectListItem> FeaturedChoices
    {
        get
        {                
            return feature.Select(f => new SelectListItem
            {
                Text = f.Key,
                Value = f.Value.ToString(),
                Selected = IsSelected(this.Spotlight.Featured, f.Key)
            });
        }
    }

    private bool IsSelected(bool featured, string val)
    {
        bool result = false;

        if (String.Compare(val, "True") == 0 && featured)
            result = true;
        else if (String.Compare(val, "False") == 0 && !featured)
            result = true;

        return result;
    }

    // constr
    public SpotlightFormViewModel(Spotlight spotlight)
    {
        Spotlight = spotlight;
    }
}

<强>控制器：

    public ActionResult Edit(int id)
    {
        Spotlight spotlight = spotlightRepository.GetSpotlight(id);

        return View(new SpotlightFormViewModel(spotlight));
    }

查看：

<div class="editor-label"> <%: Html.LabelFor(model => model.Spotlight.Featured) %> </div> <div class="editor-field"> <%: Html.DropDownListFor(model => model.FeaturedMenu, Model.FeaturedChoices)%> <%: Html.ValidationMessageFor(model => model.Spotlight.Featured) %> </div>

MVC2中的简单DropDownListFor？

2 个答案: