Question

我如何编写一个比较两个字段的自定义ValidationAttribute？这是常见的“输入密码”，“确认密码”方案。我需要确保两个字段相同并保持一致，我想通过DataAnnotations实现验证。

所以在伪代码中，我正在寻找一种方法来实现以下内容：

public class SignUpModel
{
    [Required]
    [Display(Name = "Password")]
    public string Password { get; set; }

    [Required]
    [Display(Name = "Re-type Password")]
    [Compare(CompareField = Password, ErrorMessage = "Passwords do not match")]
    public string PasswordConfirm { get; set; }
}

public class CompareAttribute : ValidationAttribute
{
    public CompareAttribute(object propertyToCompare)
    {
        // ??
    }

    public override bool IsValid(object value)
    {
        // ??
    }
}

所以问题是，我如何编码[Compare] ValidationAttribute？

Answer 1

确保您的项目引用system.web.mvc v3.xxxxx。

然后你的代码应该是这样的：

using System.Web.Mvc;

。。。

[Required(ErrorMessage = "This field is required.")]    
public string NewPassword { get; set; }

[Required(ErrorMessage = "This field is required.")]
[Compare(nameof(NewPassword), ErrorMessage = "Passwords don't match.")]
public string RepeatPassword { get; set; }

Answer 2

ASP.NET MVC 3 Framework中有一个CompareAttribute可以执行此操作。如果您正在使用ASP.NET MVC 2并以.Net 4.0为目标，那么您可以查看ASP.NET MVC 3源代码中的实现。

Answer 3

这是Darin答案的较长版本：

public class CustomAttribute : ValidationAttribute
{    
    public override bool IsValid(object value)
    {
        if (value.GetType() == typeof(Foo))
        {
           Foo bar = (Foo)value;
           //compare the properties and return the result
        }

        throw new InvalidOperationException("This attribute is only valid for Foo objects");
    }
}

和用法：

[MetadataType(typeof(FooMD))]
public partial class Foo
{
     ... functions ...
}

[Custom]
public class FooMD
{
     ... other data annotations ...
}

错误将显示在@Html.ValidationSummary(false)

中

Answer 4

您可以拥有自定义验证属性并将其应用于模型而不是单个属性。这是example你可以看一下。

Answer 5

如果你们使用MVC 4，请尝试使用此代码..它将解决您的错误..

请制作一个Metadataclass，而不是部分类impliment comfirmemail属性。请查看以下代码以获取更多详细信息。

using System;
    using System.Collections.Generic;
    using System.ComponentModel.DataAnnotations;
    using StringlenghtMVC.Comman;
    using System.Web.Mvc;

using System.Collections;

    [MetadataType(typeof(EmployeeMetaData))] //here we call metadeta class
    public partial class Employee
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }
        public Nullable<int> Age { get; set; }
        public string Gender { get; set; }
        public Nullable<System.DateTime> HireDate { get; set; }

       //[CompareAttribute("Email")]
        public string ConfirmEmail { get; set; }
    }

    public class EmployeeMetaData
    {
        [StringLength(10, MinimumLength = 5)]
        [Required]
        //[RegularExpression(@"(([A-za-Z]+[\s]{1}[A-za-z]+))$", ErrorMessage = "Please enter Valid Name")]
        public string Name { get; set; }

        [Range(1, 100)]
        public int Age { get; set; }
        [CurrentDate]
        [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
        public DateTime HireDate { get; set; }

        //[RegularExpression(@"^[\w-\._\%]+@(?:[\w]{2,6}$")]
        public string Email { get; set; }

        [System.Web.Mvc.CompareAttribute("Email")]
        public string ConfirmEmail { get; set; }


    }

Answer 6

对于未来的人们来看这个问题，我试图编写一个验证属性，如果对象的属性是某个值，它将评估正则表达式。在我的情况下，如果地址是送货地址，我不希望启用邮政信箱，所以这就是我提出的：

用法

[Required]
public EAddressType addressType { get; set; } //Evaluate Validation attribute against this

[EvaluateRegexIfPropEqualsValue(Constants.NOT_PO_BOX_REGEX, "addressType", EAddressType.Shipping, ErrorMessage = "Unable to ship to PO Boxes or APO addresses")]
public String addressLine1 { get; set; }

这是验证属性的代码：

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false)]
public class EvaluateRegexIfPropEqualsValue : ValidationAttribute
{
    Regex _regex;
    string _prop;
    object _targetValue;

    public EvaluateRegexIfPropEqualsValue(string regex, string prop, object value)
    {
        this._regex = new Regex(regex);
        this._prop = prop;
        this._targetValue = value;
    }

    bool PropertyContainsValue(Object obj)
    {
        var propertyInfo = obj.GetType().GetProperty(this._prop);
        return (propertyInfo != null && this._targetValue.Equals(propertyInfo.GetValue(obj, null)));
    }

    protected override ValidationResult IsValid(object value, ValidationContext obj)
    {
        if (this.PropertyContainsValue(obj.ObjectInstance) && value != null && !this._regex.IsMatch(value.ToString()))
        {
            return new ValidationResult(this.ErrorMessage);
        }
        return ValidationResult.Success;
    }
}

使用DataAnnotations比较两个模型属性

6 个答案: