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原文:Model Validation in Asp.net MVC 本文用于记录Pro ASP.NET MVC 3 Framework中阐述的数据验证的方式。
先说服务器端的吧。最简单的一种方式自然是直接在Action方法中来进行了，如下：
[HttpPost]
public ViewResult MakeBooking(Appointment appt)
{
if (String.IsNullOrWhiteSpace(appt.ClientName))
{
ModelState.AddModelError("ClientName", "Please enter your name");
}
if (ModelState.IsValidField("Date") && DateTime.Now > appt.Date)
{
ModelState.AddModelError("Date", "Please enter a date in the future");
}
if (!appt.TermsAccepted)
{
ModelState.AddModelError("TermsAccepted", "You must accept the terms");
}
if (ModelState.IsValidField("ClientName") && ModelState.IsValidField("Date") &&
appt.ClientName == "Joe" && appt.Date.DayOfWeek == DayOfWeek.Monday)
{
ModelState.AddModelError("", "Joe cannot book appointments on Mondays");
}
if (ModelState.IsValid)
{
repository.SaveAppointment(appt);
return View("Completed", appt);
}
else
{
return View();
}
}
补充Appointment类源码如下：
public class Appointment
{
public string ClientName { get; set; }
[DataType(DataType.Date)]
public DateTime Date { get; set; }
public bool TermsAccepted { get; set; }
}
可以看到，Appointment类很POCO，其中Date属性上的DataType属性，不过是标注Date属性值为DateTime的Date部分（去掉Time部分）。再看action内部，将传入的appointment对象属性进行了一个遍历校验。最后，ModelState.AddModelError("", "Joe cannot book appointments on Mondays");
是标注一个对象模型级别的错误（方法的key参数为空），模型级别错误可以标注多个，它们均将通过@Html.ValidationSummary()显示错误信息。
上述action对应的view为：
@model PageValidation.Models.Appointment
@{
ViewBag.Title =
"Make A Booking";
}
<h4>Book an Appointment</h4>
@using (Html.BeginForm())
{
@Html.ValidationSummary();
<p>
Your name: @Html.EditorFor(m => m.ClientName)
@Html.ValidationMessageFor(m => m.ClientName)
</p>
<p>
Appointment Date: @Html.EditorFor(m => m.Date)
@Html.ValidationMessageFor(m => m.Date)
</p>
<p>
@Html.EditorFor(m => m.TermsAccepted) I accept the terms & conditions
@Html.ValidationMessageFor(m => m.TermsAccepted)
</p>
<input type=
"submit" value=
"Make Booking" />
}
这个时候，运行程序，神马都不填写然后提交时，页面提示如下：
如果不想form中错误提示重复（顶部的summary和顶部的detail），将@Html.ValidationSummary();
更新为@Html.ValidationSummary(true); 即可。这个时候，顶部Validation Summary部分只会提示model-level错误了，比如上文中的ModelState.AddModelError("", "Joe cannot book appointments on Mondays");。
关于@Html.ValidationSummary()更多细节，请MSDN。
另外，还有一个view的问题是，Firefox和Chrome等一些浏览器上，对checkbox样式的设置不取作用，上图中的效果是通过在checkbox外层包一个div，将checkbox样式转移到div上来实现的。具体为：在项目Views\Shared\EditorTemplates目录下，建立一个Boolean.cshtml文件以覆盖asp.net mvc默认的行为。文件内容如下：
@model bool?
@if (ViewData.ModelMetadata.IsNullableValueType)
{
@Html.DropDownListFor(m => m, new SelectList(new[] { "Not Set", "True", "False" }, Model));
}
else
{
ModelState state = ViewData.ModelState[ViewData.ModelMetadata.PropertyName];
bool value = Model ?? false;
if (state != null && state.Errors.Count > 0)
{
<div class="input-validation-error" style="float: left">
@Html.CheckBox("", value)
</div>
}
else
{
@Html.CheckBox("", value)
}
}
服务器端验证第2种方式是通过Model Binder了。我们继承DefaultModelBinder来写一个Appointment需要的类：
public class ValidatingModelBinder : DefaultModelBinder
{
protected override void SetProperty(ControllerContext controllerContext, ModelBindingContext bindingContext,
PropertyDescriptor propertyDescriptor, object value)
{
// make sure we call the base implementation
base.SetProperty(controllerContext, bindingContext, propertyDescriptor, value);
// perform our property-level validation
switch (propertyDescriptor.Name)
{
case "ClientName":
if (string.IsNullOrEmpty((string)value))
{
bindingContext.ModelState.AddModelError("ClientName", "Please enter your name");
}
break;
case "Date":
if (bindingContext.ModelState.IsValidField("Date") && DateTime.Now > ((DateTime)value))
{
bindingContext.ModelState.AddModelError("Date", "Please enter a date in the future");
}
break;
case "TermsAccepted":
if (!((bool)value))
{
bindingContext.ModelState.AddModelError("TermsAccepted", "You must accept the terms");
}
break;
}
}
protected override void OnModelUpdated(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
// make sure we call the base implementation
base.OnModelUpdated(controllerContext, bindingContext);
Appointment model = bindingContext.Model as Appointment;
// apply our model-level validation
if (model != null && bindingContext.ModelState.IsValidField("ClientName") && bindingContext.ModelState.IsValidField("Date")
&& model.ClientName == "Joe" && model.Date.DayOfWeek == DayOfWeek.Monday)
{
bindingContext.ModelState.AddModelError("", "Joe cannot book appointments on Mondays");
}
}
}
其中，OnModelUpdated方法是当给model所有属性赋值时触发，SetProperty方式是当单个属性变化时即触发。接下来要做的，就是在global的Application_Start方法中注册了：
ModelBinders.Binders.Add(typeof(Appointment), new ValidatingModelBinder());
然后，MakeBooking action就可以解脱出来，只需要如下几行代码：
if (ModelState.IsValid)
{
repository.SaveAppointment(appt);
return View("Completed", appt);
}
else
{
return View();
}
此时，效果和第1种方式完全一样。
第3种方式是通过MetaData了。Asp.net MVC内置了5个meta data验证属性：Compare、Range、RegularExpression、Required、StringLength。基于这5个属性的一些限制，为了更适切Appointment类，自定义几个验证属性如下：
futureDate验证属性：
public class FutureDateValidatorAttribute : ValidationAttribute
{
public override bool IsValid(object value)
{
var isDate = value is DateTime;
if(isDate)
{
var date = Convert.ToDateTime(value);
if (date <= DateTime.Now)
{
return false;
}
}
return true;
}
}
MustBeTrue验证属性：
public class MustBeTrueAttribute : ValidationAttribute
{
public override bool IsValid(object value)
{
return value is bool && (bool)value;
}
}
Appointment验证属性：
public class AppointmentValidatorAttribute : ValidationAttribute
{
public AppointmentValidatorAttribute()
{
ErrorMessage = "Joe cannot book appointments on Mondays";
}
public override bool IsValid(object value)
{
Appointment app = value as Appointment;
if (app == null || string.IsNullOrEmpty(app.ClientName) || app.Date == null)
{
// we don‘t have a model of the right type to validate, or we don‘t have
// the values for the ClientName and Date properties we require
return true;
}
else
{
return !(app.ClientName == "Joe" && app.Date.DayOfWeek == DayOfWeek.Monday);
}
}
}
再来定义Appointment类：
[AppointmentValidator]
public class Appointment
{
[Required(ErrorMessage = "Please enter your name")]
public string ClientName { get; set; }
[DataType(DataType.Date)]
[FutureDateValidator(ErrorMessage = "You must enter a date in the future")]
public DateTime Date { get; set; }
//[Range(typeof(bool), "true", "true", ErrorMessage = "You must accept the terms")]
[MustBeTrue(ErrorMessage = "You must accept the terms")]
public bool TermsAccepted { get; set; }
}
第4种方式：通过实现IValidatableObject接口，定义自验证model。还是Appointment类，如下：
public class Appointment : IValidatableObject
{
public string ClientName { get; set; }
[DataType(DataType.Date)]
public DateTime Date { get; set; }
public bool TermsAccepted { get; set; }
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
List<ValidationResult> errors = new List<ValidationResult>();
if (string.IsNullOrEmpty(ClientName))
{
errors.Add(new ValidationResult("Please enter your name", new string[] { "ClientName" }));
}
if (DateTime.Now > Date)
{
errors.Add(new ValidationResult("Please enter a date in the future", new string[] { "Date" }));
}
if (errors.Count == 0 && ClientName == "Joe"
&& Date.DayOfWeek == DayOfWeek.Monday)
{
errors.Add(new ValidationResult("Joe cannot book appointments on Mondays"));
}
if (!TermsAccepted)
{
errors.Add(new ValidationResult("You must accept the terms", new string[] { "TermsAccepted" }));
}
return errors;
}
}
可以看到，它的核心不过是：将类对象验证内容移入到Valiate方法中。
第5种方式，通过继承ModelValidationProvider，创建自定义ValidationProvider. 如下：
public class CustomValidationProvider : ModelValidatorProvider
{
public override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata, ControllerContext context)
{
if (metadata.ContainerType == typeof(Appointment))
{
return new ModelValidator[] {
new AppointmentPropertyValidator(metadata, context)
};
}
else if (metadata.ModelType == typeof(Appointment))
{
return new ModelValidator[] {
new AppointmentValidator(metadata, context)
};
}
return Enumerable.Empty<ModelValidator>();
}
}
AppointmentPropertyValidator代码如下：
public class AppointmentPropertyValidator : ModelValidator
{
public AppointmentPropertyValidator(ModelMetadata metadata, ControllerContext context)
: base(metadata, context)
{
}
public override IEnumerable<ModelValidationResult> Validate(object container)
{
Appointment appt = container as Appointment;
if (appt != null)
{
switch (Metadata.PropertyName)
{
case "ClientName":
if (string.IsNullOrEmpty(appt.ClientName))
{
return new ModelValidationResult[]
{
new ModelValidationResult
{
//MemberName = "ClientName",
Message = "Please enter your name"
}
};
}
break;
case "Date":
if (appt.Date == null || DateTime.Now > appt.Date)
{
return new ModelValidationResult[]
{
new ModelValidationResult
{
MemberName = "",
Message = "Please enter a date in the future"
}
};
}
break;
case "TermsAccepted":
if (!appt.TermsAccepted)
{
return new ModelValidationResult[]
{
new ModelValidationResult
{
MemberName = "",
Message = "You must accept the terms"
}
};
}
break;
}
}
return Enumerable.Empty<ModelValidationResult>();
}
}
注意，上文代码中MemberName不能填写，获取赋值为空，否则error提交到ModelState时，key值会重叠，比如ClientName会成为ClientName.ClientName。AppointmentValidator代码如下：
public class AppointmentValidator : ModelValidator
{
public AppointmentValidator(ModelMetadata metadata, ControllerContext context)
: base(metadata, context)
{
}
public override IEnumerable<ModelValidationResult> Validate(object container)
{
Appointment appt = (Appointment)Metadata.Model;
if (appt.ClientName == "Joe" && appt.Date.DayOfWeek == DayOfWeek.Monday)
{
return new ModelValidationResult[]
{
new ModelValidationResult
{
MemberName = "",
Message = "Joe cannot book appointments on Mondays"
}
};
}
return Enumerable.Empty<ModelValidationResult>();
}
}
做完这些工作，然后就是注册启用CustomerValidationProvider了。在Application_Start中加入：
ModelValidatorProviders.Providers.Add(new CustomValidationProvider());
就完毕了。
关于CustomerValidationProvider这种方式，作者建议仅用于复杂场合。如：需要从db中动态加载validation rule，或者实现自己的一些验证框架时才使用。这里有一个案例：http://www.codeproject.com/Articles/463900/Creating-a-custom-ModelValidatorProvider-in-ASP-NE
好吧，再看浏览器端的验证。
第1步先启用客户端验证：
<add key=
"ClientValidationEnabled" value=
"true"/>
<add key=
"UnobtrusiveJavaScriptEnabled" value=
"true"/>
或者在Application_Start中增加：
HtmlHelper.ClientValidationEnabled = true;
HtmlHelper.UnobtrusiveJavaScriptEnabled = true;
还有，view当中确保没有：
HtmlHelper.ClientValidationEnabled = false;
默认情况下，它是true。如果要禁用，上述3个区域任意一个设置为false即可。
第2步，view中加载4个必须文件：
<link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" />
<script src="@Url.Content("~/Scripts/jquery-1.5.1.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
第3步，据说最简单的方式是利用meta data属性：
[AppointmentValidator]
public class Appointment
{
[Required(ErrorMessage = "Please enter your name")]
[StringLength(10, MinimumLength = 3, ErrorMessage = "Please enter a string of whose length is between 3 and 10")]
[EmailAddress]
public string ClientName { get; set; }
[DataType(DataType.Date)]
[FutureDateValidator(ErrorMessage = "You must enter a date in the future")]
public DateTime Date { get; set; }
[MustBeTrue(ErrorMessage = "You must accept the terms")]
public bool TermsAccepted { get; set; }
}
其中EmailAddress是新实现的一个可供客户端验证用的metadata属性。如下：
public class EmailAddressAttribute : ValidationAttribute, IClientValidatable
{
private static readonly Regex emailRegex = new Regex(".+@.+\\..+");
public EmailAddressAttribute()
{
ErrorMessage = "Enter a valid email address";
}
public override bool IsValid(object value)
{
return !string.IsNullOrEmpty((string) value) &&
emailRegex.IsMatch((string) value);
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
return new List<ModelClientValidationRule>
{
new ModelClientValidationRule
{
ValidationType = "email",
ErrorMessage = this.ErrorMessage
},
//new ModelClientValidationRule
// {
// ValidationType = "required",
// ErrorMessage = this.ErrorMessage
// }
};
}
}
它实现了一个IClientValidatable
接口，所以能够直接在客户端交互。
关于它的实现原理，它不过是在server端将view上需要验证的全部信息都render并且隐藏在页面，然后基于jQuery的validation组件来交互。 看一下html片段：
<p>
Your name: <input data-val="true" data-val-email="Enter a valid email address" data-val-length="Please enter a string of whose length is between 3 and 10" data-val-length-max="10" data-val-length-min="3" data-val-required="Please enter your name" id="ClientName" name="ClientName" type="text" value="" />
<span class="field-validation-valid" data-valmsg-for="ClientName" data-valmsg-replace="true"></span>
</p>
<p>
Appointment Date: <input class="text-box single-line" data-val="true" data-val-remote="&#39;Date&#39; is invalid." data-val-remote-additionalfields="*.Date" data-val-remote-url="/Appointment/ValidateDate" data-val-required="The Date field is required." id="Date" name="Date" type="text" value="2012/10/16" />
<span class="field-validation-valid" data-valmsg-for="Date" data-valmsg-replace="true"></span>
</p>
所以，在客户端，其实你可以脱离mvc框架自己来写。如：
$(document).ready(function () {
$(‘form‘).validate({
errorLabelContainer: ‘#validtionSummary‘,
wrapper: ‘li‘,
rules: {
ClientName: {
required: true,
}
},
messages: {
ClientName: "Please enter your name"
}
});
});
同时，在view中render时，你也可以按照自己的方式来做。如将原有的ClientName显示方式换为：
<p>
Your name: @Html.TextBoxFor(m => m.ClientName, new { data_val = "true",
data_val_email = "Enter a valid email address",
data_val_required = "Please enter your name"})
@Html.ValidationMessageFor(m => m.ClientName)
</p>
因为-在C#中是非法变量名字符，所以用_替代，同时asp.net mvc生成html时会将它替换为-。
最后一个问题是，当客户端验证需要使用服务器端资源时，怎么办？ 这时就要使用到Remote Validation了。首先，自然是得后端有一个ajax调用的action了：
public JsonResult ValidateDate(string Date)
{
DateTime parsedDate;
if (!DateTime.TryParse(Date, out parsedDate))
{
return Json("Please enter a valid date (mm/dd/yyyy)", JsonRequestBehavior.AllowGet);
}
else if (DateTime.Now > parsedDate)
{
return Json("Please enter a date in the future", JsonRequestBehavior.AllowGet);
}
else
{
return Json(true, JsonRequestBehavior.AllowGet);
}
}
然后，在Appointment类的Date属性上加个Remote特性：
[DataType(DataType.Date)]
//[FutureDateValidator(ErrorMessage = "You must enter a date in the future")]
[Remote("ValidateDate", "Appointment")]
public DateTime Date { get; set; }
至此，它就完成了。当你输入date结束后，就会调用ValidateDate(string Date)方法。 我在想，这里Appointment得是真正的ViewModel了，要不然就太别扭了。因为它实际上是调用了controller的action方法了。
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Model Validation in Asp.net MVC,布布扣,bubuko.com
Model Validation in Asp.net MVC
标签：des style blog http java color
原文地址：http://www.cnblogs.com/lonelyxmas/p/3812911.html
