Question

有没有在ViewModel上预先填充带有数据属性的SelectList？

我想做

@Html.DropdownListFor(m=> m.CityId, Model.Cities);

所以它生成如下代码：

<select id="City" class="location_city_input" name="City">
    <option data-geo-lat="-32.522779" data-geo-lng="-55.765835" data-geo-zoom="6" />
    <option data-geo-lat="-34.883611" data-geo-lng="-56.181944" data-geo-zoom="13" data-geo-name="Montevideo" data-child=".state1" value="1">Montevideo</option>               
    <option data-geo-lat="-34.816667" data-geo-lng="-55.95" data-geo-zoom="13" data-geo-name="Canelones, Ciudad de la Costa" data-child=".state41" value="41">Ciudad de la Costa</option>
</select>

Answer 1

这是一个简单的解决方案。

并非所有内容都必须使用.NET代码中的扩展方法编写。 MVC的一大优点是它可以让您轻松访问构建自己的HTML。

使用MVC4，您可以使用助手HTML.NameFor和HTML.IdFor

获取表达式树上元素的ID和名称

<select name="@Html.NameFor(Function(model) model.CityId)"
        id="@Html.IdFor(Function(model) model.CityId)"
        class="location_city_input">
    @For Each city In Model.Cities
        @<option value="@city.Value"
                 @(If(city.Value = Model.CityId, "selected", ""))
                 data-geo-lat="@city.Lat"
                 data-geo-lng="@city.Lng"
                 data-geo-zoom="@city.Zoom">
            @city.Text
        </option>
    Next
</select>

假设Model.Cities是暴露每个属性的项集合。那么你应该全力以赴。

如果您想要可重用性，请考虑将其作为可枚举城市的任何内容的编辑器模板

Answer 2

您必须扩展SelectListItem，然后扩展DropDownListFor以使用扩展的SelectListItem。

看看这个解决方案：

Adding html class tag under <option> in Html.DropDownList

Answer 3

MVC将对象名称转换为属性名称时，它将“_”与“ - ”相关联，因此它的：

@Html.DropDownList(a=>a.websiteid, Model.GetItems, new{ data_rel="selected" })

不是我的答案，回答来自ASP＆gt; NET论坛的关于bruce（sqlwork.com）的答案。

How can I add data-rel="selected" attribute into dropdownlistfor htmlAttributes?

只是希望能帮助我解决这个问题！欣赏。

Answer 4

我有类似的要求，我创建了一个扩展。希望对想要创建扩展的人有所帮助。

/*cs file*/
/*This contains your information with List<vmListItem>*/
public class vmListItem
{
   public int Id { get; set; }
   public string Name { get; set; }
   public string Tag { get; set; }
}

/*This contains the attributes in select, using List<vmAttribute>. Check cshtml */
public class vmAttribute
{
   public string Key { get; set; }
   public string Value { get; set; }
}

    /// <summary>
    /// Creates a dropdownlist using a list with data attributes included
    /// </summary>
    /// <param name="helper"></param>
    /// <param name="id">id and name of the select</param>
    /// <param name="attributes">list of attrs for select</param>
    /// <param name="items"><list of options/param>
    /// <param name="idSelected">id selected in option</param>
    /// <param name="tagName">data-tagName you can choose the name of your tag</param>
    /// <param name="textHeader">first option in select</param>
    /// <returns></returns>
    public static MvcHtmlString DropDownListForWithTag(this HtmlHelper helper, string id, List<vmAttribute> attributes, List<vmListItem> items, int idSelected, string tagName = "tag", string textHeader= "")
    {
        var select = new TagBuilder("select");
        select.GenerateId(id);
        select.MergeAttribute("name", id);
        foreach (vmAttribute att in atributos) select.MergeAttribute(att.Key, att.Value);

        TagBuilder headerOption = new TagBuilder("option");
        headerOption .MergeAttribute("value", null);
        headerOption .InnerHtml = textHeader;
        select.InnerHtml += headerOption ;

        foreach(var item in items)
        {                
            TagBuilder option = new TagBuilder("option");
            option.MergeAttribute("value", item.Id.ToString());
            option.MergeAttribute("data-" + tagName, item.Tag);
            if (idSelected == item.Id) option.MergeAttribute("selected", "selected");
            option.InnerHtml = item.Name;

            select.InnerHtml += option.ToString();
        }

        return new MvcHtmlString(select.ToString());
    }

/*cshtml file*/
@Html.DropDownListForWithTag("MovimientoBienMotivoId", new List<vmAttribute> {
                        new vmAttribute("class", "form-control"),
                        new vmAttribute("data-val", "true"),
                        new vmAttribute("data-val-required", "El campo Motivo es obligatorio"),
                        new vmAttribute("onchange", "movValidarCambioMotivo()"),
                    }, (List<vmListItem>)ViewBag.MovimientoBienMotivoId, Model.MovimientoBienMotivoId, "codigo", "Seleccione")
                    @Html.ValidationMessageFor(model => model.ColumnId, "", new { @class = "text-danger" })


/*html results*/

Answer 5

这是我最终没有扩展的方式，但是仍然使不干扰验证的功能继续起作用并绑定到ViewModel属性。

创建了一个HTML助手，以获取字符串的验证属性：

    public static IHtmlString GetUnobtrusiveValidationAttributesFor<TModel, TProperty>(this HtmlHelper<TModel> html, Expression<Func<TModel, TProperty>> propertySelector)
    {
        string propertyName = html.NameFor(propertySelector).ToString();
        ModelMetadata metaData = ModelMetadata.FromLambdaExpression(propertySelector, html.ViewData);
        IDictionary<string, object> attributeCollection = html.GetUnobtrusiveValidationAttributes(propertyName, metaData);

        return html.Raw(String.Join(" ", attributeCollection.Select(kvp => kvp.Key + "=\"" + kvp.Value.ToString() + "\"")));
    }

在视图的select列表中使用此帮助程序：

<select name="@Html.NameFor(m => m.CityId)" id="@Html.IdFor(m => m.CityId)"
    @Html.GetUnobtrusiveValidationAttributesFor(m => m.CityId)
    class="location_city_input">
    @foreach(var city in Model.Cities)
    {
        <option value="@city.Id.ToString()" @(city.Id == Model.CityId ? "selected" : "") 
            data-geo-lat="@city.Lat" data-geo-lng="@city.Lng" data-geo-zoom="@city.Zoom">
            @city.Name
        </option>
    }
</select>

这将输出如下内容：

<select id="CityId" name="CityId" 
    data-val-required="The SelectedTaxRateID field is required." data-val="true" 
    class="location_city_input">
    <option value="1" selected data-geo-lat="-34.883611" data-geo-lng="-56.181944" data-geo-zoom="13">Montevideo</option>               
    <option value="41" data-geo-lat="-34.816667" data-geo-lng="-55.95" data-geo-zoom="13">Ciudad de la Costa</option>
</select>

我将把条件data-的属性留给您，因为这些只是形成适当的Razor表达式的问题。

具有数据属性的SelectListItem

5 个答案: