MVC模型要求为真

Question

有没有办法通过数据注释要求将布尔属性设置为true？

public class MyAwesomeObj{
    public bool ThisMustBeTrue{get;set;}
}

Answer 1

您可以创建自己的验证器：

public class IsTrueAttribute : ValidationAttribute
{
    #region Overrides of ValidationAttribute

    /// <summary>
    /// Determines whether the specified value of the object is valid. 
    /// </summary>
    /// <returns>
    /// true if the specified value is valid; otherwise, false. 
    /// </returns>
    /// <param name="value">The value of the specified validation object on which the <see cref="T:System.ComponentModel.DataAnnotations.ValidationAttribute"/> is declared.
    ///                 </param>
    public override bool IsValid(object value)
    {
        if (value == null) return false;
        if (value.GetType() != typeof(bool)) throw new InvalidOperationException("can only be used on boolean properties.");

        return (bool) value;
    }

    #endregion
}

Answer 2

对于ASP.NET Core MVC，这里是基于dazbradbury解决方案的客户端和服务器验证

public class EnforceTrueAttribute : ValidationAttribute, IClientModelValidator
{
    public override bool IsValid(object value)
    {
        if (value == null) return false;
        if (value.GetType() != typeof(bool)) throw new InvalidOperationException("can only be used on boolean properties.");
        return (bool)value;
    }

    public void AddValidation(ClientModelValidationContext context)
    {
        MergeAttribute(context.Attributes, "data-val", "true");
        var errorMessage = ErrorMessage ?? 
            $"The value for field {context.ModelMetadata.GetDisplayName()} must be true.";
        MergeAttribute(context.Attributes, "data-val-enforcetrue", errorMessage);
    }

    private void MergeAttribute(IDictionary<string, string> attributes,
        string key,
        string value)
    {
        if (attributes.ContainsKey(key))
        {
            return;
        }
        attributes.Add(key, value);
    }
}

然后在客户端：

$.validator.addMethod("enforcetrue", function (value, element, param) {
    return element.checked;
});

$.validator.unobtrusive.adapters.addBool("enforcetrue");

那么用法是：

[EnforceTrue(ErrorMessage = "Please tick the checkbox")]
public bool IsAccepted { get; set; }

Answer 3

关注ta.speot.is的帖子和Jerad Rose的评论：

给定的帖子不会在客户端使用不显眼的验证。这应该适用于两个阵营（客户端和服务器）：

[RegularExpression("(True|true)")]
public bool TermsAndConditions { get; set; }

Answer 4

我不知道通过DataAnnotations的方法，但这很容易在您的控制器中完成。

public ActionResult Add(Domain.Something model)
{

    if (!model.MyCheckBox)
        ModelState.AddModelError("MyCheckBox", "You forgot to click accept");

    if (ModelState.IsValid) {
        //'# do your stuff
    }

}

唯一的另一种选择是为服务器端构建自定义验证器，为客户端构建remote validator（远程验证仅在MVC3 +中可用）

Answer 5

这对我有用。没有别的。 Mvc 5：

模型

public string True
{
  get
  {
    return "true";
  }
}

[Required]
[Compare("True", ErrorMessage = "Please agree to the Acknowlegement")]
public bool Acknowlegement { get; set; }

视图

  @Html.HiddenFor(m => m.True)
  @Html.EditorFor(model => model.Acknowlegement, new { htmlAttributes = Model.Attributes })
  @Html.ValidationMessageFor(model => model.Acknowlegement, "", new { @class = "text-danger" })

Answer 6

我认为处理这个问题的最佳方法是检查控制器是否为真，否则只需在模型中添加错误并重新显示您的视图。

如前所述，所有[必需]确实存在一个值，在您的情况下，如果没有检查，您仍然会得到错误。

Answer 7

查看万无一失的验证here。您可以通过Nuget下载/安装它。

对于这种事情来说，这是一个很棒的小图书馆。

Answer 8

/// <summary> 
///  Summary : -CheckBox for or input type check required validation is not working the root cause and solution as follows
///
///  Problem :
///  The key to this problem lies in interpretation of jQuery validation 'required' rule. I digged a little and find a specific code inside a jquery.validate.unobtrusive.js file:
///  adapters.add("required", function (options) {
///  if (options.element.tagName.toUpperCase() !== "INPUT" || options.element.type.toUpperCase() !== "CHECKBOX") {
///    setValidationValues(options, "required", true);
///    }
///   });
///   
///  Fix: (Jquery script fix at page level added in to check box required area)
///  jQuery.validator.unobtrusive.adapters.add("brequired", function (options) {
///   if (options.element.tagName.toUpperCase() == "INPUT" && options.element.type.toUpperCase() == "CHECKBOX") {
///              options.rules["required"] = true;
///   if (options.message) {
///                   options.messages["required"] = options.message;
///                       }
///  Fix : (C# Code for MVC validation)
///  You can see it inherits from common RequiredAttribute. Moreover it implements IClientValidateable. This is to make assure that rule will be propagated to client side (jQuery validation) as well.
///  
///  Annotation example :
///   [BooleanRequired]
///   public bool iAgree { get; set' }
/// </summary>


public class BooleanRequired : RequiredAttribute, IClientValidatable
{

    public BooleanRequired()
    {
    }

    public override bool IsValid(object value)
    {
        return value != null && (bool)value == true;
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        return new ModelClientValidationRule[] { new ModelClientValidationRule() { ValidationType = "brequired", ErrorMessage = this.ErrorMessage } };
    }
}

Answer 9

我会为服务器和客户端创建一个验证器。使用MVC和不显眼的表单验证，只需执行以下操作即可实现：

首先，在项目中创建一个类来执行服务器端验证，如下所示：

public class EnforceTrueAttribute : ValidationAttribute, IClientValidatable
{
    public override bool IsValid(object value)
    {
        if (value == null) return false;
        if (value.GetType() != typeof(bool)) throw new InvalidOperationException("can only be used on boolean properties.");
        return (bool)value == true;
    }

    public override string FormatErrorMessage(string name)
    {
        return "The " + name + " field must be checked in order to continue.";
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        yield return new ModelClientValidationRule
        {
            ErrorMessage = String.IsNullOrEmpty(ErrorMessage) ? FormatErrorMessage(metadata.DisplayName) : ErrorMessage,
            ValidationType = "enforcetrue"
        };
    }
}

在此之后，在模型中注释相应的属性：

[EnforceTrue(ErrorMessage=@"Error Message")]
public bool ThisMustBeTrue{ get; set; }

最后，通过在View中添加以下脚本来启用客户端验证：

<script type="text/javascript">
    jQuery.validator.addMethod("enforcetrue", function (value, element, param) {
        return element.checked;
    });
    jQuery.validator.unobtrusive.adapters.addBool("enforcetrue");
</script>

注意：我们已经创建了一个方法GetClientValidationRules，它将我们的注释从我们的模型推送到视图。

如果使用资源文件提供国际化的错误消息，请删除FormatErrorMessage调用（或只调用基数）并调整GetClientValidationRules方法，如下所示：

public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
    string errorMessage = String.Empty;
    if(String.IsNullOrWhiteSpace(ErrorMessage))
    {
        // Check if they supplied an error message resource
        if(ErrorMessageResourceType != null && !String.IsNullOrWhiteSpace(ErrorMessageResourceName))
        {
            var resMan = new ResourceManager(ErrorMessageResourceType.FullName, ErrorMessageResourceType.Assembly);
            errorMessage = resMan.GetString(ErrorMessageResourceName);
        }
    }
    else
    {
        errorMessage = ErrorMessage;
    }

    yield return new ModelClientValidationRule
    {
        ErrorMessage = errorMessage,
        ValidationType = "enforcetrue"
    };
}

Answer 10

我知道这是一篇较旧的帖子，但想分享一个简单的服务器端方式来做到这一点。您创建一个设置为true的公共属性，并将您的bool与该属性进行比较。如果未选中您的bool（默认为false），则表单将不会验证。

public bool isTrue
{ get { return true; } }

[Required]
[Display(Name = "I agree to the terms and conditions")]
[Compare("isTrue", ErrorMessage = "Please agree to Terms and Conditions")]
public bool iAgree { get; set; }

Answer 11

我尝试了几种解决方案，但它们都没有完全为我提供客户端和服务器端验证。那么我在MVC 5应用程序中做了什么让它工作：

在ViewModel中（用于服务器端验证）：

public bool IsTrue => true;

[Required]
[Display(Name = "I agree to the terms and conditions")]
[Compare(nameof(IsTrue), ErrorMessage = "Please agree to Terms and Conditions")]
public bool HasAcceptedTermsAndConditions { get; set; }

在Razor页面中（用于客户端验证）：

<div class="form-group">
   @Html.CheckBoxFor(m => m.HasAcceptedTermsAndConditions)
   @Html.LabelFor(m => m.HasAcceptedTermsAndConditions)
   @Html.ValidationMessageFor(m => m.HasAcceptedTermsAndConditions)

   @Html.Hidden(nameof(Model.IsTrue), "true")
</div>

Answer 12

我想引导人们到下面的小提琴：https://dotnetfiddle.net/JbPh0X

用户将[Range(typeof(bool), "true", "true", ErrorMessage = "You gotta tick the box!")]添加到其布尔属性中，这会导致服务器端验证工作。

为了使客户端验证工作，他们添加了以下脚本：

// extend jquery range validator to work for required checkboxes
var defaultRangeValidator = $.validator.methods.range;
$.validator.methods.range = function(value, element, param) {
    if(element.type === 'checkbox') {
        // if it's a checkbox return true if it is checked
        return element.checked;
    } else {
        // otherwise run the default validation function
        return defaultRangeValidator.call(this, value, element, param);
    }
}

Answer 13

只需检查其字符串表示是否等于True：

[RegularExpression("True")]
public bool TermsAndConditions { get; set; }

Answer 14

您可以创建自己的属性或使用CustomValidationAttribute。

这是您使用CustomValidationAttribute的方式：

[CustomValidation(typeof(BoolValidation), "ValidateBool")]

其中BoolValidation定义为：

public class BoolValidation
{
  public static ValidationResult ValidateBool(bool boolToBeTrue)
  {
    if (boolToBeTrue)
    {
      return ValidationResult.Success;
    }
    else
    {
      return new ValidationResult(
          "Bool must be true.");
    }
  }

Answer 15

[Required]属性代表需要任何值 - 它可以是真或假。你必须使用另一个验证。

Answer 16

你有appropriate items set up in the web.config吗？

这可能导致验证无效。

您还可以尝试创建自定义验证属性（因为[Required]只关心它是否存在，并且您关心该值）：

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false)]
sealed public class RequiredTrueAttribute : ValidationAttribute
{
    // Internal field to hold the mask value.
    readonly bool accepted;

    public bool Accepted
    {
        get { return accepted; }
    }

    public RequiredTrueAttribute(bool accepted)
    {
        this.accepted = accepted;
    }

    public override bool IsValid(object value)
    {
        bool isAccepted = (bool)value;
        return (isAccepted == true);
    }

    public override string FormatErrorMessage(string name)
    {
        return String.Format(CultureInfo.CurrentCulture,
          ErrorMessageString, name, this.Accepted);
    }
}

然后，用法：

[RequiredTrue(ErrorMessage="{0} requires acceptance to continue.")]
public bool Agreement {get; set;}

来自here。