Asp.net MVC 示例项目"Suteki.Shop"分析之---数据验证

在Suteki.Shop，实现了自己的数据校验机制，可以说其设计思路还是很有借鉴价值的。而使用
这种机制也很容易在Model中对相应的实体对象（属性）添加校验操作方法。下面就来介绍一下其实
现方式。

首先，看一下这样类图：

public static class ValidationExtensions
{
public static ValidationProperty<T> Label<T>(this T value, string label)
{
return new ValidationProperty<T>(value, label);
}
}

public class ValidationProperty<T>
{
T value;
string label;

public ValidationProperty(T value, string label)
{
this.value = value;
this.label = label;
}

public bool IsObject
{
get { return typeof (object).IsAssignableFrom(typeof (T)); }
}

public bool IsString
{
get { return (IsObject && typeof (string).IsAssignableFrom(typeof (T))); }
}

public string ValueAsString
{
get { return value as string; }
}

public T Value
{
get { return value; }
}

public ValidationProperty<T> IsRequired()
{
if (value == null)
{
throw new ValidationException(label, StringExtensions.With("You must enter a value for {0}", label));
}
if (IsString && string.IsNullOrEmpty(ValueAsString))
{
throw new ValidationException(label, StringExtensions.With("You must enter a value for {0}", label));
}

return this;
}

public ValidationProperty<T> IsNumeric()
{
if(IsString)
{
// the obvious thing (int.Parse) doesn't work for very long strings of digits
if (ValueAsString.Trim().Any(c => !char.IsDigit(c)))
{
throw new ValidationException(label,"{0} must be a number e.g. 240".With(label));
}
}

return this;
}

public ValidationProperty<T> IsDecimal()
{
if (IsString && ValueAsString.Trim().Any(c => !(char.IsDigit(c) || c == '.')))
{
throw new ValidationException(label,"{0} must be a decimal number e.g 12.30".With(label));
}

return this;
}

public ValidationProperty<T> IsNonZero()
{
int test;
if (!int.TryParse(value.ToString(), out test))
{
throw new ValidationException(label,"{0} must be a non-zero number".With(label));
}
if (test == 0)
{
throw new ValidationException(label,"{0} must be non-zero".With(label));
}
return this;
}

public ValidationProperty<T> WithMaxLength(int maxLength)
{
if (IsString && ValueAsString.Length > maxLength)
{
throw new ValidationException(label,"{0} must not exceed {1} characters".With(label, maxLength));
}
return this;
}

public ValidationProperty<T> WithLengthRange(IEnumerable<int> range)
{
if (IsString && ValueAsString.Length < range.Min() || ValueAsString.Length > range.Max())
{
throw new ValidationException(label,
"{0} length must be between {1} and {2} characters".With(label, range.Min(), range.Max()));
}

return this;
}

public ValidationProperty<T> IsEmail()
{
// ignore is null or empty, use IsRequired in parrallel to check this if needed
if (!IsString) return this;

if (string.IsNullOrEmpty(ValueAsString)) return this;

const string patternLenient = @"\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*";
if (!Regex.Match(ValueAsString, patternLenient).Success)
{
throw new ValidationException(label,"{0} must be a valid email address".With(label));
}

return this;
}

public ValidationProperty<T> IsCreditCard()
{
if (IsString)
{
var trimmedValue = Regex.Replace(value.ToString(), "[^0-9]", "");

trimmedValue.Label(label).IsNumeric().WithLengthRange(13.To(19));

var numbers = trimmedValue.Trim().Reverse().Select(c => int.Parse(c.ToString()));

var oddSum = numbers.AtOddPositions().Sum();
var doubleEvenSum = numbers.AtEvenPositions().SelectMany(i => new[] { (i * 2) % 10, (i * 2) / 10 }).Sum();

if ((oddSum + doubleEvenSum) % 10 != 0)
{
throw new ValidationException(label, "{0} is not a valid credit card number".With(label));
}
}
return this;
}
}

使用它就可以很方便的对Model中的相关属性添加验证规则了。以User为例，其验证规则添加
内容如下（Suteki.Shop\Models\User.cs）：

public void Validate()
{
Validator validator = new Validator
{
() => Email.Label("Email").IsRequired().IsEmail(),
() => Password.Label("Password").IsRequired(),
};

validator.Validate();
}

在规则添加完成后，就把对获取到的信息进行验证了，下面是验证的实现方法：

public class Validator : List<Action>
{
public void Validate()
{
var errors = new List<ValidationException>();

foreach (Action validation in this)
{
try
{
validation();
}
catch (ValidationException validationException)
{
errors.Add(validationException);
}
}

if (errors.Count > 0)
{
//backwards compatibility
string error = string.Join("", errors.Select(x => x.Message + "<br />").ToArray());
throw new ValidationException(error, errors);
}
}
}

代码比较简单，大家看一下就可以了。

到这里，主要的代码就介绍完了，下面再后到UserController中看看Action是如何调用验证方法
并发验证错误信息复制到ModelState中的，接着看一下编辑用户信息这个Action：

[AcceptVerbs(HttpVerbs.Post), UnitOfWork]
public ActionResult Edit([DataBind] User user, string password)
{
if(! string.IsNullOrEmpty(password))
{
user.Password = userService.HashPassword(password);
}

try
{
user.Validate();
}
catch (ValidationException validationException)
{
validationException.CopyToModelState(ModelState, "user");
return View("Edit", EditViewData.WithUser(user));
}

return View("Edit", EditViewData.WithUser(user).WithMessage("Changes have been saved"));
}

大家看到了吧，Try中的user.Validate()就是启动验证的功能，而在Catch中使用CopyToModelState
方法将错误信息Copy到当前Controller中的ModelState中，如下：

public void CopyToModelState(ModelStateDictionary dictionary, string prefix)
{
foreach(var error in errors)
{
string key = string.IsNullOrEmpty(prefix) ? error.propertyKey : prefix + "." + error.propertyKey;

dictionary.AddModelError(key, error.Message);
}
}

这样在前台View中，通过Html.ValidationSummary()方法来显示验证结果，现在我们看一下最终的
运行效果：

以“输入错误的Email地址”为例：



好了，今天的内容就先到这里了。

原文链接:/article/4598195.html

作者: daizhj,代震军,LaoD

Tags: mvc,Suteki.Shop

网址: http://daizhj.cnblogs.com/