asp.net-mvc mvc4 数据注释比较两个日期

mvc4 data annotation compare two dates

提问by user2208349

I have these two fields in my model:

我的模型中有这两个字段：

[Required(ErrorMessage="The start date is required")]
[Display(Name="Start Date")]
[DisplayFormat(DataFormatString = "{0,d}")]
public DateTime startDate { get; set; }

[Required(ErrorMessage="The end date is required")]
[Display(Name="End Date")]
[DisplayFormat(DataFormatString = "{0,d}")]
public DateTime endDate{ get; set; }

I require that endDatemust be greater than startDate. I tried using [Compare("startDate")]but this only works for the equal operation.

我要求endDate必须大于startDate. 我尝试使用，[Compare("startDate")]但这仅适用于相等的操作。

What should I use for the "greater than" operation?

对于“大于”操作，我应该使用什么？

回答by Davor Zlotrg

Take a look at Fluent Validationor MVC Foolproof Validation: those can help you a lot.

看看Fluent Validation或MVC Foolproof Validation：这些可以帮助你很多。

With Foolproof for example there is a [GreaterThan("StartDate")]annotation than you can use on your date property.

例如，对于 Foolproof，有一个[GreaterThan("StartDate")]注释，您可以在日期属性上使用。

Or if you don't want to use other libraries, you can implement your own custom validation by implementing IValidatableObjecton your model:

或者，如果您不想使用其他库，您可以通过IValidatableObject在您的模型上实现来实现您自己的自定义验证：

public class ViewModel: IValidatableObject
{
    [Required]
    public DateTime StartDate { get; set; }
    [Required]    
    public DateTime EndDate { get; set; } 

    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
    {
       if (EndDate < StartDate)
       {
           yield return 
             new ValidationResult(errorMessage: "EndDate must be greater than StartDate",
                                  memberNames: new[] { "EndDate" });
       }
    }
}

回答by Mahbub

IValidatableObject interface provides a way for an object to be validated which implements IValidatableObject.Validate(ValidationContext validationContext) method. This method always return IEnumerable object. That's why you should create list of ValidationResult objects and errors are added to this and return. Empty list means to validate your conditions. That is as follows in mvc 4...

IValidatableObject 接口提供了一种验证对象的方法，该方法实现了 IValidatableObject.Validate(ValidationContext validationContext) 方法。此方法始终返回 IEnumerable 对象。这就是为什么您应该创建 ValidationResult 对象列表，并将错误添加到其中并返回。空列表意味着验证您的条件。那就是在mvc 4...

 public class LibProject : IValidatableObject
{
    [Required(ErrorMessage="Project name required")]

    public string Project_name { get; set; }
    [Required(ErrorMessage = "Job no required")]
    public string Job_no { get; set; }
    public string Client { get; set; }
    [DataType(DataType.Date,ErrorMessage="Invalid Date")]
    public DateTime ExpireDate { get; set; }


    IEnumerable<ValidationResult> IValidatableObject.Validate(ValidationContext validationContext)
    {
        List < ValidationResult >  res =new List<ValidationResult>();
        if (ExpireDate < DateTime.Today)
        {
            ValidationResult mss=new ValidationResult("Expire date must be greater than or equal to Today");
            res.Add(mss);

        }
        return res; 
    }
}

回答by Jeffrey Roughgarden

Borrowing heavily from the responses from Alexander Gore and Jaime Marín in a related StackOverflow question1, I created five classes that enable comparing two fields in the same model using GT, GE, EQ, LE, and LT operators, provided they implement IComparable. So it can be used for pairs of dates, times, integers, and strings, for example.

大量借鉴 Alexander Gore 和 Jaime Marín 在相关 StackOverflow 问题1中的回答，我创建了五个类，这些类可以使用 GT、GE、EQ、LE 和 LT 运算符比较同一模型中的两个字段，前提是它们实现了 IComparable。例如，它可以用于日期、时间、整数和字符串对。

It would be nice to merge these all into one class and take the operator as an argument, but I don't know how. I left the three exceptions as is because, if thrown, they really represent a form design problem, not a user input problem.

将所有这些合并到一个类中并将运算符作为参数会很好，但我不知道如何。我保留了这三个异常，因为如果抛出它们，它们确实代表了表单设计问题，而不是用户输入问题。

You just use it in your model like this, and the file with the five classes follows:

您只需像这样在模型中使用它，包含五个类的文件如下：

    [Required(ErrorMessage = "Start date is required.")]
    public DateTime CalendarStartDate { get; set; }

    [Required(ErrorMessage = "End date is required.")]
    [AttributeGreaterThanOrEqual("CalendarStartDate", 
        ErrorMessage = "The Calendar end date must be on or after the Calendar start date.")]
    public DateTime CalendarEndDate { get; set; }


using System;
using System.ComponentModel.DataAnnotations;

//Contains GT, GE, EQ, LE, and LT validations for types that implement IComparable interface.
//https://stackoverflow.com/questions/41900485/custom-validation-attributes-comparing-two-properties-in-the-same-model

namespace DateComparisons.Validations
{
    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter)]
    public class AttributeGreaterThan : ValidationAttribute
    {
        private readonly string _comparisonProperty;
        public AttributeGreaterThan(string comparisonProperty){_comparisonProperty = comparisonProperty;}

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        if(value==null) return new ValidationResult("Invalid entry");

        ErrorMessage = ErrorMessageString;

        if (value.GetType() == typeof(IComparable)) throw new ArgumentException("value has not implemented IComparable interface");
        var currentValue = (IComparable)value;

        var property = validationContext.ObjectType.GetProperty(_comparisonProperty);
        if (property == null) throw new ArgumentException("Comparison property with this name not found");

        var comparisonValue = property.GetValue(validationContext.ObjectInstance);
        if(!ReferenceEquals(value.GetType(), comparisonValue.GetType()))
            throw new ArgumentException("The types of the fields to compare are not the same.");

        return currentValue.CompareTo((IComparable)comparisonValue) > 0 ? ValidationResult.Success : new ValidationResult(ErrorMessage);
    }
}

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter)]
public class AttributeGreaterThanOrEqual : ValidationAttribute
{
    private readonly string _comparisonProperty;
    public AttributeGreaterThanOrEqual(string comparisonProperty) { _comparisonProperty = comparisonProperty; }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        if (value == null) return new ValidationResult("Invalid entry");
        ErrorMessage = ErrorMessageString;

        if (value.GetType() == typeof(IComparable)) throw new ArgumentException("value has not implemented IComparable interface");
        var currentValue = (IComparable)value;

        var property = validationContext.ObjectType.GetProperty(_comparisonProperty);
        if (property == null) throw new ArgumentException("Comparison property with this name not found");

        var comparisonValue = property.GetValue(validationContext.ObjectInstance);
        if (!ReferenceEquals(value.GetType(), comparisonValue.GetType()))
            throw new ArgumentException("The types of the fields to compare are not the same.");

        return currentValue.CompareTo((IComparable)comparisonValue) >= 0 ? ValidationResult.Success : new ValidationResult(ErrorMessage);

    }
}

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter)]
public class AttributeEqual : ValidationAttribute
{
    private readonly string _comparisonProperty;
    public AttributeEqual(string comparisonProperty) { _comparisonProperty = comparisonProperty; }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        if (value == null) return new ValidationResult("Invalid entry");
        ErrorMessage = ErrorMessageString;

        if (value.GetType() == typeof(IComparable)) throw new ArgumentException("value has not implemented IComparable interface");
        var currentValue = (IComparable)value;

        var property = validationContext.ObjectType.GetProperty(_comparisonProperty);
        if (property == null) throw new ArgumentException("Comparison property with this name not found");

        var comparisonValue = property.GetValue(validationContext.ObjectInstance);
        if (!ReferenceEquals(value.GetType(), comparisonValue.GetType()))
            throw new ArgumentException("The types of the fields to compare are not the same.");

        return currentValue.CompareTo((IComparable)comparisonValue) == 0 ? ValidationResult.Success : new ValidationResult(ErrorMessage);
    }
}

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter)]
public class AttributeLessThanOrEqual : ValidationAttribute
{
    private readonly string _comparisonProperty;
    public AttributeLessThanOrEqual(string comparisonProperty) { _comparisonProperty = comparisonProperty; }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        if (value == null) return new ValidationResult("Invalid entry");
        ErrorMessage = ErrorMessageString;

        if (value.GetType() == typeof(IComparable)) throw new ArgumentException("value has not implemented IComparable interface");
        var currentValue = (IComparable)value;

        var property = validationContext.ObjectType.GetProperty(_comparisonProperty);
        if (property == null) throw new ArgumentException("Comparison property with this name not found");

        var comparisonValue = property.GetValue(validationContext.ObjectInstance);
        if (!ReferenceEquals(value.GetType(), comparisonValue.GetType()))
            throw new ArgumentException("The types of the fields to compare are not the same.");

        return currentValue.CompareTo((IComparable)comparisonValue) <= 0 ? ValidationResult.Success : new ValidationResult(ErrorMessage);
    }
}

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter)]
public class AttributeLessThan : ValidationAttribute
{
    private readonly string _comparisonProperty;
    public AttributeLessThan(string comparisonProperty) { _comparisonProperty = comparisonProperty; }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        if (value == null) return new ValidationResult("Invalid entry");
        ErrorMessage = ErrorMessageString;

        if (value.GetType() == typeof(IComparable)) throw new ArgumentException("value has not implemented IComparable interface");
        var currentValue = (IComparable)value;

        var property = validationContext.ObjectType.GetProperty(_comparisonProperty);
        if (property == null) throw new ArgumentException("Comparison property with this name not found");

        var comparisonValue = property.GetValue(validationContext.ObjectInstance);
        if (!ReferenceEquals(value.GetType(), comparisonValue.GetType()))
            throw new ArgumentException("The types of the fields to compare are not the same.");

        return currentValue.CompareTo((IComparable)comparisonValue) < 0 ? ValidationResult.Success : new ValidationResult(ErrorMessage);
    }
}

}

}

---

---