netcore 开发问题整理(下拉框)

页面绑定

 //第一条 无 如果后台绑定类型INT 会报错 
@Html.DropDownList("Classify", (ViewBag.Classify), "无", new { @class = "form-control" })

推荐使用
<select asp-for="Classify" name="Classify" asp-items="ViewBag.Classify" class="form-control">
　　<option value="0">无所属</option>
</select>

后台数据绑定

public IActionResult Index()
{
　　ViewBag.Classify = GetClassifyList();
　　return View();
}

/// <summary>
/// 下拉框绑定
/// </summary>
/// <returns></returns>

public List<SelectListItem> GetClassifyList()
{
　　List<SelectListItem> list= new List<SelectListItem>();
　　list.Add(new SelectListItem("鞋", "1"));
　　list.Add(new SelectListItem("衣", "2"));
　　list.Add(new SelectListItem("日用", "3"));
　　list.Add(new SelectListItem("厨房", "4"));

　　return list;
}

/// <summary>
/// 下拉框绑定 读取数据库
/// </summary>
/// <returns></returns>
public List<SelectListItem> GetClassifyList()
{
　　List<SelectListItem> list= (from x in Classify()
　　select new SelectListItem
　　{
　　　　Text = x,
　　　　Value = x
　　}).ToList();
　　return list;
}

页面直接绑定枚举

<select asp-for="Quantityunits" name="Quantityunits" asp-items="Html.GetEnumSelectList<EnumModel.EnumQuantityunits>()" class="form-control">
</select>

枚举类

        /// <summary>
        /// 数量单位
        /// </summary>
        public enum EnumQuantityunits
        {
            [Display(Name = "件")]
            [Description("件")]
            Piece = 1,
            [Display(Name = "瓶")]
            [Description("瓶")]
            Bottle = 2,
            [Display(Name = "打")]
            [Description("打")]
            Dozen = 3,
            [Display(Name = "箱")]
            [Description("箱")]
            Boxful = 4,
            [Display(Name = "千克")]
            [Description("千克")]
            KG = 5,
            [Display(Name = "克")]
            [Description("克")]
            G = 6
        }