@model RegisterViewModel

@{
    ViewBag.Title = "用户注册";
}

<h1>用户注册</h1>
<div class="row">
    <div class="col-md-12">
        <form method="post">
            <div asp-validation-summary="All" class="text-danger"></div>
            <div class="form-group">
                <label asp-for="Email"></label>
                <input asp-for="Email" class="form-control" />
                <span asp-validation-for="Email" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Password"></label>
                <input asp-for="Password" class="form-control" />
                <span asp-validation-for="Password" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="ConfirmPassword"></label>
                <input asp-for="ConfirmPassword" class="form-control" />
                <span asp-validation-for="ConfirmPassword" class="text-danger"></span>
            </div>

            <div class="form-group">
                <label asp-for="City"></label>
                <input asp-for="City" class="form-control" />
            </div>

            <button type="submit" class="btn btn-primary">注册</button>
        </form>
    </div>
</div>

    public class RegisterViewModel
    {
        [Required]
        [Display(Name = "邮箱地址")]
        [EmailAddress]
        [Remote(action: "IsEmailInUse", controller: "Account")]public string Email { get; set; }

        [Required]
        [Display(Name = "密码")]
        [DataType(DataType.Password)]
        public string Password { get; set; }

        [DataType(DataType.Password)]
        [Display(Name = "确认密码")]
        [Compare("Password",
            ErrorMessage = "密码与确认密码不一致，请重新输入.")]
        public string ConfirmPassword { get; set; }



        public string City { get; set; }
    }

{
  "version": "1.0",
  "defaultProvider": "cdnjs",
  "libraries": [
    {
      "library": "[email protected]",
      "destination": "wwwroot/lib/twitter-bootstrap/"
    },
    {
      "library": "[email protected]",
      "destination": "wwwroot/lib/jquery/"
    },
    {
      "library": "[email protected]",
      "destination": "wwwroot/lib/jquery-validate/"
    },
    {
      "library": "[email protected]",
      "destination": "wwwroot/lib/jquery-validation-unobtrusive/"
    }
  ]

[Remote(action: "IsEmailInUse", controller: "Account")]

[AcceptVerbs("Get", "Post")]
[AllowAnonymous]
public async Task<IActionResult> IsEmailInUse(string email)
{
    var user = await userManager.FindByEmailAsync(email);

    if (user == null)
    {
        return Json(true);
    }
    else
    {
        return Json($"邮箱： {email} 已经被注册使用了。");
    }
}