MVC模型绑定

视图：

@model RegisterViewModel
@{
    ViewData["Title"] = "Register";
}

<h2>@ViewData["Title"]</h2>

<div class="row">
    <div class="col-md-4">
        <form asp-route-returnUrl="@ViewData["ReturnUrl"]" method="post">
            <h4>Create a new account.</h4>
            <hr />
            <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>
            <button type="submit" class="btn btn-default">Register</button>
        </form>
    </div>
</div>

@section Scripts {
    @await Html.PartialAsync("_ValidationScriptsPartial")
}

对应的控制器操作：

  [HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Register(RegisterViewModel model /*隐式模型绑定*/, string returnUrl = null)
        {
            var testModel = new TestRegisterModel();
            await TryUpdateModelAsync(testModel); //显示模型绑定，从请求的视图中更新当前模型对象

            ViewData["ReturnUrl"] = returnUrl;
            if (ModelState.IsValid)
            {
                var user = new ApplicationUser { UserName = model.Email, Email = model.Email };
                var result = await _userManager.CreateAsync(user, model.Password);
                if (result.Succeeded)
                {
                    _logger.LogInformation("User created a new account with password.");

                    var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
                    var callbackUrl = Url.EmailConfirmationLink(user.Id, code, Request.Scheme);
                    await _emailSender.SendEmailConfirmationAsync(model.Email, callbackUrl);

                    await _signInManager.SignInAsync(user, isPersistent: false);
                    _logger.LogInformation("User created a new account with password.");
                    return RedirectToLocal(returnUrl);
                }
                AddErrors(result);
            }

            // If we got this far, something failed, redisplay form
            return View(model);
        }

隐式绑定参数RegisterViewModel的定义：

 public class RegisterViewModel
    {
        [Required]
        [EmailAddress]
        [Display(Name = "Email")]
        public string Email { get; set; }

        [Required]
        [StringLength(100, ErrorMessage = "The {0} must be at least {2} and at max {1} characters long.", MinimumLength = 6)]
        [DataType(DataType.Password)]
        [Display(Name = "Password")]
        public string Password { get; set; }

        [DataType(DataType.Password)]
        [Display(Name = "Confirm password")]
        [Compare("Password", ErrorMessage = "The password and confirmation password do not match.")]
        public string ConfirmPassword { get; set; }
    }

显式绑定参数TestRegisterModel的定义：

public class TestRegisterModel
    {
        public string Sex { get; set; }
        public string Email { get; set; }
    }

• 当操作中有参数时，模型绑定会隐式的工作；如果操作中无参数，则可以使用UpdateModel()和TryUpdateModel()方法显式地调用模型绑定；
• MVC模型绑定根据参数类型的属性（比如：ID，Title等等），会对应的在请求的视图中寻找对应的相同name属性值的控件的值，并将其传递给该参数的属性上；如果表单中不存在请求中的属性值，则参数的该属性将被自动赋值为空（NULL）；