MVC模型要求为真

Question

是否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

我会为服务器端和客户端创建验证器。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（或只调用基础）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 2

我知道这是一篇较旧的帖子，但想分享一个简单的服务器方式来做到这一点。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。如果未检查您的bool（默认为false），表单将无法验证。

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 3

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 4

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。所以我在MVC 5应用程序中做了什么让它工作：

在您的ViewModel中（用于服务器端验证）：

GetCommandLineA()

在您的Razor页面中（用于客户端验证）：

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; }

Answer 5

我想将人们引导到以下小提琴：https://dotnetfiddle.net/JbPh0X

用户添加了 [Range(typeof(bool), "true", "true", ErrorMessage = "You gotta tick the box!")]到他们的布尔属性，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 6

只需检查其字符串表示是否等于True：

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

Answer 7

您可以创建自己的属性，也可以使用CustomValidationAttribute。

这是您使用CustomValidationAttribute：

的方法

[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 8

[Required]属性代表要求任何值 - 它可以是true或false。你必须使用另一个验证。

Answer 9

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

这可能导致验证失效。

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。

Answer 10

关注ta.speot.is的帖子以及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）：

<div class="checkboxAndLabel">
    <input type="checkbox" id="{{shape.id}}" name="checkbox"
       ng-model="shape.isSelected" ng-click="controller.addOrRemoveShape(shape)"/>
    <label for="{{shape.id}}"></label>
</div>

Answer 11

对于 ASP.NET Core MVC ，这是基于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);
    }
}

然后在客户端上：

$.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 12

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
    }

}

唯一的另一个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 13

我尝试使用fields.cage的答案，但它对我而言并不奏效，但做了一些简单的事情，而且我不确定为什么（不同的Razor版本？），但是我要做的就是这个：

[Required]
[Range(typeof(bool), "true", "true", ErrorMessage = "Agreement required.")]
[Display(Name = "By clicking here, I agree that my firstborn child will etc etc...")]
public bool Agreement1Checked { get; set; }

在.cshtml文件中：

@Html.CheckBoxFor(m => m.Agreement1Checked)
@Html.LabelFor(m => m.Agreement1Checked)
@Html.ValidationMessageFor(m => m.Agreement1Checked)

Answer 14

我认为处理此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视图即可。

如前所述，所有[必需]确实存在一个值，如果没有检查，你仍然会得到错误。

Answer 15

/// <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 16

.NET Core MVC-带有数据注释的必需复选框

public class MyModel
{
    [Display(Name = "Confirmation")]
    [Range(typeof(bool), "true", "true", ErrorMessage = "Please check the Confirmation checkbox.")]
    public bool IsConfirmed { get; set; }   
}

<div class="custom-control custom-checkbox col-10">
    <input type="checkbox" asp-for="IsConfirmed" class="custom-control-input" />
    <label class="custom-control-label" for="IsConfirmed">
        "By clicking 'submit', I confirm."
    </label>
    <span asp-validation-for="IsConfirmed" class="text-danger"></span>
</div>

<script src="~/lib/jquery-validation/dist/jquery.validate.js"></script>
<script src="~/lib/jquery-validation-unobtrusive/jquery.validate.unobtrusive.js"></script>

<script type="text/javascript">
    $(document).ready(function () {
        // extend range validator method to treat checkboxes differently
        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);
            }
        }
    });
</script>