如何根据复选框值验证文本框

Question

我正在尝试根据复选框值验证文本框。请查看我的模型类和 IsValid 覆盖方法。

public class Product
{
    //Below property value(HaveExperiance)
    [MustBeProductEntered(HaveExperiance)] 
    public string ProductName { get; set; }

    public bool HaveExperiance { get; set; }
}

public class MustBeTrueAttribute : ValidationAttribute
{
    //Here i need the value of HaveExperiance property which 
    //i passed from  [MustBeProductEntered(HaveExperiance)]  in product class above.
    public override bool IsValid(object value)
    {
        return value is bool && (bool)value;
    }
}

您可以在上面的product 类中的ProductName 属性中看到我正在尝试传递HaveExperiance 类属性值，如果选中，则用户必须填写ProductName 文本框。

所以我最初的问题是，如何根据 HaveExperiance 值验证 ProductName 文本框，提前致谢。

编辑：

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Data.Entity;
using System.Linq;
using System.Reflection;
using System.Web;
using System.Web.Mvc;

namespace Mvc.Affiliates.Models
{
    public class MyProducts
    {
        [Key]
        [Required(ErrorMessage = "Please insert product id.")]
        public string ProductId { get; set; }

        [RequiredIf("HaveExperiance")]
        public string ProductName { get; set; }

        public bool HaveExperiance { get; set; }
        public List<MyProducts> prolist { get; set; }
    }

    public class RequiredIfAttribute : ValidationAttribute
    {
        private RequiredAttribute _innerAttribute = new RequiredAttribute();

        public string Property { get; set; }

        public object Value { get; set; }

        public RequiredIfAttribute(string typeProperty)
        {
            Property = typeProperty;
        }

        public RequiredIfAttribute(string typeProperty, object value)
        {
            Property = typeProperty;
            Value = value;
        }

        public override bool IsValid(object value)
        {
            return _innerAttribute.IsValid(value);
        }
    }

    public class RequiredIfValidator : DataAnnotationsModelValidator<RequiredIfAttribute>
    {
        public RequiredIfValidator(ModelMetadata metadata, ControllerContext context, RequiredIfAttribute attribute) : base(metadata, context, attribute) { }

        public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
        {
            return base.GetClientValidationRules();
        }

        public override IEnumerable<ModelValidationResult> Validate(object container)
        {
            PropertyInfo field = Metadata.ContainerType.GetProperty(Attribute.Property);

            if (field != null)
            {
                var value = field.GetValue(container, null);

                if ((value != null && Attribute.Value == null) || (value != null && value.Equals(Attribute.Value)))
                {
                    if (!Attribute.IsValid(Metadata.Model))
                    {
                        yield return new ModelValidationResult { Message = ErrorMessage };
                    }
                }
            }
        }
    }

控制器

public class HomeController : Controller
    {
        //
        // GET: /Home/

        MvcDbContext _db = new MvcDbContext();
        public ActionResult Index()
        {
          return View();
        }

        [HttpPost]
        public ActionResult Index(MyProducts model)
        {
            string ProductId = model.ProductId;
            string ProductName = model.ProductName;
            //bool remember = model.HaveExperiance;
            return View();
        }
    }

查看

@model   Mvc.Affiliates.Models.MyProducts
@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Details</h2>
<br />

<div style="height:200px; width:100%">
  @using  (Html.BeginForm("Index","Home", FormMethod.Post))
    {

   <h2>Details</h2>

        @Html.LabelFor(model => model.ProductId)
        @Html.TextBoxFor(model => model.ProductId)

        @Html.LabelFor(model => model.ProductName)
        @Html.EditorFor(model => model.ProductName)
        @Html.ValidationMessageFor(model => model.ProductName, "*")

        @Html.CheckBoxFor(model => model.HaveExperiance)
        @Html.ValidationMessageFor(model => model.HaveExperiance, "*")
       <input type="submit" value="Submit" />
  }

</div>

到目前为止，我已经尝试了上面的代码，实际上我需要当我单击复选框时，它应该开始验证我的 ProductName 文本框，如果取消选中则不是。我在上面的代码中遗漏了一点东西，请帮助并纠正我。

Answer 1

这是一个如何基于另一个属性创建自定义验证属性的完整示例：

public class RequiredIfAttribute : ValidationAttribute
{
    private RequiredAttribute _innerAttribute = new RequiredAttribute();

    public string Property { get; set; }

    public object Value { get; set; }

    public RequiredIfAttribute(string typeProperty) {
        Property = typeProperty;
    }

    public RequiredIfAttribute(string typeProperty, object value)
    {
        Property = typeProperty;
        Value = value;
    }

    public override bool IsValid(object value)
    {
        return _innerAttribute.IsValid(value);
    }
}

public class RequiredIfValidator : DataAnnotationsModelValidator<RequiredIfAttribute>
{
    public RequiredIfValidator(ModelMetadata metadata, ControllerContext context, RequiredIfAttribute attribute) : base(metadata, context, attribute) { }

    public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
    {
        return base.GetClientValidationRules();
    }

    public override IEnumerable<ModelValidationResult> Validate(object container)
    {
        PropertyInfo field = Metadata.ContainerType.GetProperty(Attribute.Property);

        if (field != null) {
            var value = field.GetValue(container, null);

            if ((value != null && Attribute.Value == null) || (value != null && value.Equals(Attribute.Value))) {
                if (!Attribute.IsValid(Metadata.Model)) {
                    yield return new ModelValidationResult { Message = ErrorMessage };
                }
            }
        }
    }
}

在Global.asax文件Application_Start中添加这部分：

DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(RequiredIfAttribute), typeof(RequiredIfValidator));

这部分是注册RequiredIfValidator所必需的，否则MVC将只使用RequiredIfAttribute而忽略RequiredIfValidator。

如果你想验证ProductName 是否HaveExperiance 有一个值：

[RequiredIf("HaveExperiance")]
public string ProductName { get; set; }

如果您想仅在 HaveExperiance 为 false 时验证 ProductName：

[RequiredIf("HaveExperiance", false)]
public string ProductName { get; set; }

如果您想验证 ProductName 仅当 HaveExperiance 为真：

[RequiredIf("HaveExperiance", true)]
public string ProductName { get; set; }

在RequiredIfAttribute 类中，我创建了一个RequiredAttribute 对象，仅用于验证传递给IsValid 方法的值。

Property 字段用于保存激活验证的属性的名称。在RequiredIfValidator类中使用反射（field.GetValue(container, null)）获取磁场电流值。

当您在代码中调用验证时（例如，当您执行 if(TryValidateModel(model)) 时）首先调用 RequiredIfValidator 类，然后在某些条件有效时调用 RequiredIfAttribute（通过 Attribute.IsValid(Metadata.Model)）类 ((value != null && Attribute.Value == null) || (value != null && value.Equals(Attribute.Value))) .

最后一件事。因为RequiredIfAttribute 继承自ValidationAttribute，所以您也可以像使用任何其他验证属性一样使用错误消息。

[RequiredIf("HaveExperiance", true, ErrorMessage = "The error message")]
public string ProductName { get; set; }

[RequiredIf("HaveExperiance", true, ErrorMessageResourceName = "ResourceName", ErrorMessageResourceType = typeof(YourResourceType))]
public string ProductName { get; set; }