Asp.net MVC源码分析--Model Validation(Server端)实现(1)

一.MVC Validation 用法:
在Asp.net MVC 框架中如果需要对Model 对象加入验证,我们可以在Model的属性上标记所有继承于ValidationAttribute的Attribute特性.
例如下面的代码中,StringLength/Range/Compare 都是继承于ValidationAttribute类.
 public class LogOnModel
    {
        [Required]     
        [StringLength(10)]
        public string UserName { get; set; }

        [Required]
        [Range(5,10)]
        public string Password { get; set; }

       [Compare("NewPassword", ErrorMessage = "The new      password and confirmation password do not match.")]
        public string ConfirmPassword { get; set; }

        [Display(Name = "Remember me?")]
        public bool RememberMe { get; set; }
    }
复制代码
在Action 中我们可以调用 ValidateModel 方法对Model对象进行验证,如果验证没有通过则会抛出InvalidOperationException异常，同时ModelState.IsValid状态为false
   [HttpPost]
        public ActionResult LogOn(LogOnModel model, string returnUrl)
        {         
            this.ValidateModel(model);
            if (ModelState.IsValid)
            {
                if (MembershipService.ValidateUser(model.UserName, model.Password))
                {
                    FormsService.SignIn(model.UserName, model.RememberMe);
                    if (Url.IsLocalUrl(returnUrl))
                    {
                        return Redirect(returnUrl);
                    }
                    else
                    {
                        return RedirectToAction("Index", "Home");
                    }
                }
                else
                {
                    ModelState.AddModelError("", "The user name or password provided is incorrect.");
      &nb