设置 SelectedListItem 剃须刀的索引

Question

我正在使用 as

填充下拉列表

[Required(ErrorMessage = "Please make a selection")]
    public string SelectedPrimary { get; set; }
    public IEnumerable<SelectListItem> PrimaryDrop { get; set; }

public void populateDropdown()
    {
        primaryDrop = new List<string>();
        primaryDrop.Insert(0, "Getting ready");
        primaryDrop.Insert(1, "Starting");
        primaryDrop.Insert(2, "All");
        PrimaryDrop = primaryDrop.Select(item => new SelectListItem { Value = item, Text = item });
    }

然后我的剃刀视图如下

 @Html.DropDownListFor(m => m.SelectedPrimary, new SelectList(Model.PrimaryDrop, "Value", "Text"), "Learning Path", new { style = "width:207px;", id = "FirstDropDown" })

检查元素后我会看到这个

<select data-val="true" data-val-required="Please make a selection" id="FirstDropDown" name="SelectedPrimary" style="width:207px;">
     <option value="">Learning Path</option>
     <option value="Getting ready">Getting ready</option>
     <option value="Starting">Starting</option>
   <option value="All modules">All</option>
    </select>

我怎样才能将值设置为索引？

<select data-val="true" data-val-required="Please make a selection" id="FirstDropDown" name="SelectedPrimary" style="width:207px;">
     <option value="0">Learning Path</option>
     <option value="1">Getting ready</option>
     <option value="2">Starting</option>
   <option value="3">All modules</option>
    </select>

Answer 1

您可以这样填写 PrimaryDrop（使用 List<T>.IndexOf(T) 得到 Value）

primaryDrop = new List<string>();
primaryDrop.Insert(0, "Getting ready");
primaryDrop.Insert(1, "Starting");
primaryDrop.Insert(2, "All");
PrimaryDrop = primaryDrop.Select(item => new SelectListItem 
{ 
    Value = primaryDrop.IndexOf(item), 
    Text = item 
});

Answer 2

您可以只使用字典来构建选择列表。然后使用key作为value，value作为text

var primaryDrop = new Dictionary<string, string>() { 
            {"0", "Getting Ready"},
            {"1", "Starting"},
            {"2", "All"}            
        };
PrimaryDrop = primaryDrop.Select(item => 
    new SelectListItem { Value = item.Key, Text = item.Value });

设置 SelectedListItem 剃须刀的索引

Setting index of SelectedListItem razor

asp.net-mvc

razor

drop-down-menu