model-view-controller – 比较Dates DataAnnotations验证asp.net mvc

假设我有一个StartDate和一个EndDate,我想检查EndDate是否距离开始日期不超过3个月

public class DateCompare : ValidationAttribute 
 {
    public String StartDate { get; set; }
    public String EndDate { get; set; }

    //Constructor to take in the property names that are supposed to be checked
    public DateCompare(String startDate,String endDate)
    {
        StartDate = startDate;
        EndDate = endDate;
    }

    public override bool IsValid(object value)
    {
        var str = value.ToString();
        if (string.IsNullOrEmpty(str))
            return true;

        DateTime theEndDate = DateTime.ParseExact(EndDate,"yyyy-MM-dd HH:mm:ss",CultureInfo.InvariantCulture);
        DateTime theStartDate = DateTime.ParseExact(StartDate,CultureInfo.InvariantCulture).AddMonths(3);
        return (DateTime.Compare(theStartDate,theEndDate) > 0);
    }
}

我想将此实现到我的验证中

[DateCompare(“StartDate”,“EndDate”,ErrorMessage = “The Deal can only be 3 months long!”)]

我知道我在这里得到了一个错误……但我怎样才能在asp.net mvc中进行这种业务规则验证

解决方法

>创建属性类：

public class DateCompareValidationAttribute : ValidationAttribute,IClientValidatable
{

  public enum CompareType
  {
      GreatherThen,GreatherThenOrEqualTo,EqualTo,LessThenOrEqualTo,LessThen
  }




  private CompareType _compareType;
  private DateTime _fromDate;
  private DateTime _toDate;

  private string _propertyNameToCompare;

  public DateCompareValidationAttribute(CompareType compareType,string message,string compareWith = "")
{
    _compareType = compareType;
    _propertyNameToCompare = compareWith;
    ErrorMessage = message;
}


#region IClientValidatable Members
/// <summary>
/// Generates client validation rules
/// </summary>
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata,ControllerContext context)
{
    ValidateAndGetCompareToProperty(metadata.ContainerType);
    var rule = new ModelClientValidationRule();

    rule.ErrorMessage = ErrorMessage;
    rule.ValidationParameters.Add("comparetodate",_propertyNameToCompare);
    rule.ValidationParameters.Add("comparetype",_compareType);
    rule.ValidationType = "compare";

    yield return rule;
}

#endregion


 protected override ValidationResult IsValid(object value,ValidationContext validationContext)
{
     // Have to override IsValid method. If you have any logic for server site validation,put it here. 
    return ValidationResult.Success;

}

/// <summary>
/// verifies that the compare-to property exists and of the right types and returnes this property
/// </summary>
/// <param name="containerType">Type of the container object</param>
/// <returns></returns>
private PropertyInfo ValidateAndGetCompareToProperty(Type containerType)
{
    var compareToProperty = containerType.GetProperty(_propertyNameToCompare);
    if (compareToProperty == null)
    {
        string msg = string.Format("Invalid design time usage of {0}. Property {1} is not found in the {2}",this.GetType().FullName,_propertyNameToCompare,containerType.FullName);
        throw new ArgumentException(msg);
    }
    if (compareToProperty.PropertyType != typeof(DateTime) && compareToProperty.PropertyType != typeof(DateTime?))
    {
        string msg = string.Format("Invalid design time usage of {0}. The type of property {1} of the {2} is not DateType",containerType.FullName);
        throw new ArgumentException(msg);
    }

    return compareToProperty;
}
}

注意：如果要验证时间长度,请向约束器添加另一个参数,并更改此特定类型的比较的枚举数
>将属性添加到字段中,如下所示：[DateCompareValidation(DateCompareValidationAttribute.CompareType.GreatherThenOrEqualTo,“此日期必须在另一个日期或之后”,compareWith：“AnotherDate”)]
>记下生成的html是如何更改的.它应包括验证消息,比较日期的字段名称等.生成的parms将以“data-val-compare”开头.在GetClientValidationRules方法中设置ValidationType =“compare”时,您定义了此“比较”.
>现在您需要匹配javascript代码：添加验证适配器和验证方法.我在这里使用了无限的方法,但你不必这样做.我建议将此代码放在一个单独的javascript文件中,以便此文件与您的属性类一起变得像一个控件,可以在任何地方使用.

$.validator.unobtrusive.adapters.add(
‘compare’,
[‘comparetodate’,‘comparetype’],
function (options) {
options.rules[‘compare’] = options.params;
options.messages[‘compare’] = options.message;
}
);

$.validator.addMethod("compare",function (value,element,parameters) {
    // value is the actuall value entered 
    // element is the field itself,that contain the the value (in case the value is not enough)

    var errMsg = "";
    // validate parameters to make sure everyting the usage is right
    if (parameters.comparetodate == undefined) {
        errMsg = "Compare validation cannot be executed: comparetodate parameter not found";
        alert(errMsg);
        return false;
    }
    if (parameters.comparetype == undefined) {
        errMsg = "Compare validation cannot be executed: comparetype parameter not found";
        alert(errMsg);
        return false;
    }


    var compareToDateElement = $('#' + parameters.comparetodate).get();
    if (compareToDateElement.length == 0) {
        errMsg = "Compare validation cannot be executed: Element to compare " + parameters.comparetodate + " not found";
        alert(errMsg);
        return false;
    }
    if (compareToDateElement.length > 1) {
        errMsg = "Compare validation cannot be executed: more then one Element to compare with id " + parameters.comparetodate + " found";
        alert(errMsg);
        return false;
    }
    //debugger;

    if (value && !isNaN(Date.parse(value))) {
        //validate only the value contains a valid date. For invalid dates and blanks non-custom validation should be used    
        //get date to compare
        var compareToDateValue = $('#' + parameters.comparetodate).val();
        if (compareToDateValue && !isNaN(Date.parse(compareToDateValue))) {
            //if date to compare is not a valid date,don't validate this
            switch (parameters.comparetype) {
                case 'GreatherThen':
                    return new Date(value) > new Date(compareToDateValue);
                case 'GreatherThenOrEqualTo':
                    return new Date(value) >= new Date(compareToDateValue);
                case 'EqualTo':
                    return new Date(value) == new Date(compareToDateValue);
                case 'LessThenOrEqualTo':
                    return new Date(value) <= new Date(compareToDateValue);
                case 'LessThen':
                    return new Date(value) < new Date(compareToDateValue);
                default:
                    {
                        errMsg = "Compare validation cannot be executed: '" + parameters.comparetype + "' is invalid for comparetype parameter";
                        alert(errMsg);
                        return false;
                    }
            }
            return true;
        }
        else
            return true;

    }
    else
        return true;
});

这只关注客户端不显眼的验证.如果你需要服务器端,你必须在isValid方法的覆盖中有一些逻辑.此外,您可以使用Reflection使用显示属性等生成错误消息,并使消息参数可选.

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