.Net Core表单定义

创建表单

 <form asp-controller="Account"
       asp-action="Login"
       asp-route-returnurl="@ViewData["ReturnUrl"]"
       method="post" class="form-horizontal">
 </form>

Input 输入框

<input asp-for="Name" />  

type:

.NET type	Input Type
Bool	type=”checkbox”
String	type=”text”
DateTime	type=”datetime”
Byte	type=”number”
Int	type=”number”
Single, Double	type=”number”

checkbox 多选

<input type="checkbox" asp-for="selected" />同意协议
 
定义为bool类型：public bool selected { get; set; }

textarea 多文本输入框

<textarea asp-for="Description"></textarea>

select 下拉选择

 <select asp-for="Country" asp-items="Model.Countries"></select>
 
定义类Class：
        public string Country { get; set; }
        public List<SelectListItem> Countries { get; } = new List<SelectListItem>
        {
            new SelectListItem { Value = "MX", Text = "Mexico" },
            new SelectListItem { Value = "CA", Text = "Canada" },
            new SelectListItem { Value = "US", Text = "USA"  },
        };
 
控制函数Controller：
 public IActionResult Index(FormModel model)
        {
            if (ModelState.IsValid)
            {
                var msg = model.Country + " selected";
                return RedirectToAction("IndexSuccess", new { message = msg });
            }
            return View(model);
        }

在定义类Country的时候定义为： public IEnumerable<string> Country { get; set; }即可设置为可多选的选项；

默认不想选择数组中的第一个，可以设置为“请选择”：

 <select asp-for="Country" asp-items="Model.Countries">
        <option value="">请选择</option>
 </select> 

Option Group

下拉选择分组选项：

 public FormModel()
        {
            var NorthAmericaGroup = new SelectListGroup { Name = "North America" };
            var EuropeGroup = new SelectListGroup { Name = "Europe" };

            Countries = new List<SelectListItem>
         {
             new SelectListItem
             {
                 Value = "MEX",
                 Text = "Mexico",
                 Group = NorthAmericaGroup
             },
             new SelectListItem
             {
                 Value = "CAN",
                 Text = "Canada",
                 Group = NorthAmericaGroup
             },
             new SelectListItem
             {
                 Value = "US",
                 Text = "USA",
                 Group = NorthAmericaGroup
             },
             new SelectListItem
             {
                 Value = "FR",
                 Text = "France",
                 Group = EuropeGroup
             },
             new SelectListItem
             {
                 Value = "ES",
                 Text = "Spain",
                 Group = EuropeGroup
             },
             new SelectListItem
             {
                 Value = "DE",
                 Text = "Germany",
                 Group = EuropeGroup
             }
       };
        }
        public string Country { get; set; }
        public List<SelectListItem> Countries { get; }