数据注释 - 使用属性扩展并在资源文件中存储正则表达式

Question

我目前正在使用MVC4数据注释来处理验证.我正在开发一个非常国际化的网站,因此我将所有文本保存在资源文件中.

我还想在资源文件中保留正则表达式以进行验证,这样我就可以使用相同的代码来检查,例如,Post Codes(UK)和Zip Codes(US),只需使用不同的RegEx(以及不同名称的资源等) ).

我有以下属性已经从资源文件中提取错误消息.我怎样才能从资源文件中获取正则表达式？

[RegularExpression(@"^[\w]{1,2}[0-9]{1,2}[\w]?\s?[0-9]{1,2}[\w]{1,2}$", ErrorMessageResourceType = typeof(Resources.ValidationMessages), ErrorMessageResourceName = "validPostcode")]

编辑(再次)

我现在在哪里

按照下面的答案和一些额外的搜索,我有以下内容:

在Global.asax.cs我添加了以下行,以确保调用客户端验证

DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(LocalisedAttribute), typeof(RegularExpressionAttributeAdapter));

在我的模型中,我调用了属性扩展

[Localised(typeof(Resources.FormValidation), "postcodeRegEx", "postcodeMsg")]

最后,本地化正则表达式验证的属性扩展

public class LocalisedAttribute : RegularExpressionAttribute
{
    public LocalisedAttribute(Type resource, string regularExpression, string errorMessage) 
        : base(GetRegex(regularExpression))
    {
        ErrorMessageResourceType = resource;
        ErrorMessageResourceName = errorMessage;
    }

    private static string GetRegex(string value) 
    {
        return Resources.FormValidation.ResourceManager.GetString(value);


    }
}

这是有效的,但只是我第一次在启动应用程序时使用它.

我将打开另一个问题来解决这个问题 - 它与原始请求没有直接关系,似乎与大多数人的实现没有关系,似乎并不特定于数据注释.

Answer 1

我已经有了一些扩展的RegularExpressionAttribute实现，允许使用正则表达式模式的资源。看起来像：

public class RegularExpressionExAttribute : RegularExpressionAttribute, IClientValidatable
{        
    private Regex regex { get; set; }
    private string pattern;

    private string resourceName;
    private Type resourceType;

    /// <summary>
    /// constructor, calls base with ".*" basic regex
    /// </summary>
    /// <param name="resName">resource key</param>
    /// <param name="resType">resource type</param>
    public RegularExpressionExAttribute(string resName, Type resType)
        : base(".*")
    {
        resourceName = resName;
        resourceType = resType;
    }

    /// <summary>
    /// override RegularExpressionAttribute property
    /// </summary>
    public new string Pattern
    {
        get
        {
            SetupRegex();
            return pattern;
        }
    }

    /// <summary>
    /// loads regex from resources
    /// </summary>
    private void SetupRegex()
    {
        ResourceAccessor ra = new ResourceAccessor(resourceName, resourceType);
        pattern = ra.resourceValue;
        regex = new Regex(pattern);
    }

    /// <summary>
    /// override validation with our regex
    /// </summary>
    /// <param name="value">string for validation</param>
    /// <returns></returns>
    public override bool IsValid(object value)
    {
        SetupRegex();
        string val = Convert.ToString(value);
        if (string.IsNullOrEmpty(val))
            return true;
        var m = regex.Match(val);
        return (m.Success && (m.Index == 0));
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metaData, ControllerContext controllerContext)
    {
        yield return new ModelClientValidationRegexRule(base.ErrorMessageString, this.Pattern);
    }
}

它还使用ResourceAccessor类来获取正则表达式的资源

public class ResourceAccessor
{
    private string resourceName;
    private Type resourceType;
    private Func<string> accessor;
    private string _resourceValue;

    public ResourceAccessor(string resourceName, Type resourceType)
    {
        this.resourceName = resourceName;
        this.resourceType = resourceType;
    }

    public string resourceValue
    {
        get
        {
            SetupAccessor();
            return accessor();
        }
    }

    private void SetupAccessor()
    {
        if (accessor != null) //already set
            return;
        string localValue = _resourceValue;
        bool flag1 = !string.IsNullOrEmpty(resourceName);
        bool flag2 = !string.IsNullOrEmpty(localValue);
        bool flag3 = resourceType != (Type)null;
        if (flag1 == flag2)
        {
            throw new InvalidOperationException("Can't set resource value");
        }
        if (flag3 != flag1)
        {
            throw new InvalidOperationException("Resource name and type required");
        }
        if (flag1)
            PropertyLookup();
        else
        {
            accessor = (Func<string>)(() => localValue);
        }
    }

    private void PropertyLookup()
    {
        if (resourceType == (Type)null || string.IsNullOrEmpty(resourceName))
        {
            throw new InvalidOperationException("Resource name and type required");
        }

        PropertyInfo property = resourceType.GetProperty(resourceName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static);
        if (property != (PropertyInfo)null)
        {
            MethodInfo getMethod = property.GetGetMethod(true);
            if (getMethod == (MethodInfo)null || !getMethod.IsAssembly && !getMethod.IsPublic)
                property = (PropertyInfo)null;
        }
        if (property == (PropertyInfo)null)
        {
            throw new InvalidOperationException("Resource type doesn't have property");
        }
        else if (property.PropertyType != typeof(string))
        {
            throw new InvalidOperationException("Resource type must be string");
        }
        else
        {
            accessor = (Func<string>)(() => (string)property.GetValue((object)null, (object[])null));
        }
    }
}

这是使用示例：

public class SignUpInput
{        
    [RegularExpressionEx("EmailValidationRegex", typeof(LocalizedResources), ErrorMessageResourceType = typeof(Messages), ErrorMessageResourceName = "invalidEmail")]     
    public string Email { get; set; }
}