学习笔记：ASP.NET MVC2 之验证
大家好，最近忙于工作，现在又有空闲了，现在一起来温习一下ASP.NET MVC 2 的Validation功能。
ASP.NET MVC2 支持2种验证模式，一种是前端验证，一种是服务端验证。我们一般做项目都是2种一起用的。先使用前端验证的好处毋庸置疑，因为它是在客户端执行的，它会把错误消息直接反馈给客户而无须经过服务器的处理，这样就节省了服务器宝贵的资源。而之后的服务器验证呢，又能保证数据的严格符合规格。
第一步：好，我们先来建立一个叫做Order的Model。
namespace MvcApplication1.Models
{
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
public class Order
{
[Required(ErrorMessage = "First Name is required")]
[DisplayName("First Name")]
[StringLength(160)]
public string FirstName { get; set; }
[Required(ErrorMessage = "Last Name is required")]
[DisplayName("Last Name")]
[StringLength(160)]
public string LastName { get; set; }
[Required(ErrorMessage = "Address is required")]
[StringLength(70)]
public string Address { get; set; }
}
}
在这个Model里面，这些Required,StringLength代表的就是你的验证规则。比较详细的验证规则见以下列表：
代码中的ErrorMessage表示显示在页面上的错误信息。
你甚至可以写一个自定义的验证类，比如一个简单的例子，我需要让FirstName这个字段必须不以下划线开头，我们可以这么写：
首先创建一个类，叫做FirstNameAttribute，它必须继承ValidationAttribute这个类。
namespace MvcApplication1.Models
{
using System.ComponentModel.DataAnnotations;
public class FirstNameAttribute : ValidationAttribute
{
public override bool IsValid(object value)
{
if (value == null)
return false;
if (value.ToString().StartsWith("_"))
return false;
return true;
}
}
}
然后我们就能在FirstName这个字段上加上一个约束的规则。
[Required(ErrorMessage = "First Name is required")]
[DisplayName("First Name")]
[StringLength(160)]
[FirstName(ErrorMessage="First Name can't start with \"_\"")]
public string FirstName { get; set; }
第二步：我们现在来建立一个View。
<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MvcApplication1.Models.Order>" %>
<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
Order
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<h2>
Order</h2>
<%using (Html.BeginForm())
{ %>
<ul>
<li>
<%:Html.LabelFor(m=>m.FirstName) %><%:Html.TextBoxFor(m=>m.FirstName) %><%:Html.ValidationMessageFor(m=>m.FirstName) %>
</li>
<li>
<%:Html.LabelFor(m=>m.LastName) %><%:Html.TextBoxFor(m=>m.LastName) %><%:Html.ValidationMessageFor(m=>m.LastName) %>
</li>
<li>
<%:Html.LabelFor(m=>m.Address) %><%:Html.TextBoxFor(m=>m.Address) %><%:Html.ValidationMessageFor(m=>m.Address) %>
</li>
<input type="submit" value="Save" />
</ul>
<%} %>
</asp:Content>
第三步：在Controller里面加入要处理你这个提交的请求的controller Method.
[HttpPost]
public ActionResult Order(Order orderModel)
{
if (ModelState.IsValid)
{
//Do what you want
return RedirectToAction("Index");
}
else
{
return View(orderModel);
}
}
到这里，一个服务器端的验证已经完成，可以试用一下效果：
好了，如果要想实现前段验证，只需要做以下几个简单的步骤就可以实现了：
将这三个js加入到你的master page里面：
<script src="http://www.cnblogs.com/Scripts/MicrosoftAjax.js" type="text/javascript"></script>
<script src="http://www.cnblogs.com/Scripts/MicrosoftMvcAjax.js" type="text/javascript"></script>
<script src="http://www.cnblogs.com/Scripts/MicrosoftMvcValidation.js" type="text/javascript"></script>
接着在你的 using (Html.BeginForm())之前加入以下代码：
<%Html.EnableClientValidation(); %>
这样就大功告成了，有心的朋友可以发现，你刷新完页面后，代码里面多了一些js代码，这些应该就是实现前段验证的代码：
<script type="text/javascript">
//<![CDATA[
if (!window.mvcClientValidationMetadata) { window.mvcClientValidationMetadata = []; }
window.mvcClientValidationMetadata.push({"Fields":[{"FieldName":"FirstName","ReplaceValidationMessageContents":true,"ValidationMessageId":"FirstName_validationMessage","ValidationRules":[{"ErrorMessage":"The field First Name must be a string with a maximum length of 160.","ValidationParameters":{"minimumLength":0,"maximumLength":160},"ValidationType":"stringLength"},{"ErrorMessage":"First Name is required","ValidationParameters":{},"ValidationType":"required"}]},{"FieldName":"LastName","ReplaceValidationMessageContents":true,"ValidationMessageId":"LastName_validationMessage","ValidationRules":[{"ErrorMessage":"The field Last Name must be a string with a maximum length of 160.","ValidationParameters":{"minimumLength":0,"maximumLength":160},"ValidationType":"stringLength"},{"ErrorMessage":"Last Name is required","ValidationParameters":{},"ValidationType":"required"}]},{"FieldName":"Address","ReplaceValidationMessageContents":true,"ValidationMessageId":"Address_validationMessage","ValidationRules":[{"ErrorMessage":"Address is required","ValidationParameters":{},"ValidationType":"required"},{"ErrorMessage":"The field Address must be a string with a maximum length of 70.","ValidationParameters":{"minimumLength":0,"maximumLength":70},"ValidationType":"stringLength"}]}],"FormId":"form0","ReplaceValidationSummary":false});
//]]>
</script>
好了，至此为止，我们已经完成了温习ASP.NET MVC2的Validation这个重要的功能。
