可选地使用必填字段和 ASP.NET MVC 数据注释

Question

我在 ASP.NET MVC 项目中使用 EF 数据注释，对于必填字段，我定义如下所示的字段：

型号：

[Required(ErrorMessage = "Required!");
public string PhoneHome{ get; set; }

[Required(ErrorMessage = "Required!");
public string PhoneWork{ get; set; }

[Required(ErrorMessage = "Required!");
public string PhoneMobile { get; set; }

查看：

@Html.TextBoxFor(m => m.PhoneHome)
@Html.ValidationMessageFor(m => m.PhoneHome, null, new { @class = "field-validation-error" })

@Html.TextBoxFor(m => m.PhoneWork)
@Html.ValidationMessageFor(m => m.PhoneWork, null, new { @class = "field-validation-error" })

@Html.TextBoxFor(m => m.PhoneMobile )
@Html.ValidationMessageFor(m => m.PhoneMobile , null, new { @class = "field-validation-error" })

我只想将这些字段中的一个设为必填（如果用户填写其中一个字段就可以了，但如果他没有填写任何一个字段，我想显示一条错误消息并且不要让他提交表单)，但不知道执行此操作的最合适和更智能的方法？我应该在提交时使用 JavaScript 检查所有这些字段并显示必要的错误消息吗？还是我应该只使用数据注释来执行此操作？

Answer 1

好的，我举了一个例子。我创建了一个自定义验证属性，其中包含一些参数，例如需要哪些属性以及有多少（最小和最大）。命名不是最好的，但可以完成工作（未经测试）。如果您不关心客户端上的验证（使用 jquery 验证，不引人注目......），您可以删除 ICientValidatable。

属性是这样制作的：

public class OptionalRequired : ValidationAttribute, IClientValidatable
{
    /// <summary>
    /// The name of the client validation rule
    /// </summary>
    private readonly string type = "optionalrequired";

    /// <summary>
    /// The (minimum) amount of properties that are required to be filled in. Use -1 when there is no minimum. Default 1.
    /// </summary>
    public int MinimumAmount { get; set; } = 1;
    /// <summary>
    /// The maximum amount of properties that need to be filled in. Use -1 when there is no maximum. Default -1.
    /// </summary>
    public int MaximumAmount { get; set; } = -1;

    /// <summary>
    /// The collection of property names
    /// </summary>
    public string[] Properties { get; set; }


    public OptionalRequired(string[] properties)
    {
        Properties = properties;
    }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        int validPropertyValues = 0;

        // Iterate the properties in the collection
        foreach (var propertyName in Properties)
        {
            // Find the property
            var property = validationContext.ObjectType.GetProperty(propertyName);

            // When the property is not found throw an exception
            if (property == null)
                throw new ArgumentException($"Property {propertyName} not found.");

            // Get the value of the property
            var propertyValue = property.GetValue(validationContext.ObjectInstance);

            // When the value is not null and not empty (very simple validation)
            if (propertyValue != null && String.IsNullOrEmpty(propertyValue.ToString()))
                validPropertyValues++;
        }

        // Check if the minimum allowed is exceeded
        if (MinimumAmount != -1 && validPropertyValues < MinimumAmount)
            return new ValidationResult($"You are required to fill in a minimum of {MinimumAmount} fields.");

        // Check if the maximum allowed is exceeded
        else if (MaximumAmount != -1 && validPropertyValues > MaximumAmount)
            return new ValidationResult($"You can only fill in {MaximumAmount} of fields");

        // 
        else
            return ValidationResult.Success;
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
    {
        ModelClientValidationRule rule = new ModelClientValidationRule();

        rule.ErrorMessage = "Enter your error message here or manipulate it on the client side";
        rule.ValidationParameters.Add("minimum", MinimumAmount);
        rule.ValidationParameters.Add("maximum", MaximumAmount);
        rule.ValidationParameters.Add("properties", string.Join(",", Properties));

        rule.ValidationType = type;

        yield return rule;
    }
}

你在你的类/视图模型上这样使用它：

public class Person
{
    [OptionalRequired(new string[] { nameof(MobileNumber), nameof(LandLineNumber), nameof(FaxNumber) }, MinimumAmount = 2)]
    public string MobileNumber { get; set; }
    public string LandLineNumber { get; set; }
    public string FaxNumber { get; set; }
}

使用此配置，您需要填写至少 2 个必填字段，否则将显示错误。 您可以将属性放在每个属性上，以便在所有属性上弹出错误消息。这就是你想要的

对于客户端验证，我在属性上添加了接口并设置了不同的参数，但我没有 JavaScript 本身。你需要查一下（例如here）

此代码未经测试，但我认为它可以让您很好地了解事情是如何完成的。

Answer 2

public class MyModel : IValidatableObject
{
    [Required(ErrorMessage = "Required!");
    public string PhoneHome{ get; set; }

    [Required(ErrorMessage = "Required!");
    public string PhoneWork{ get; set; }

    [Required(ErrorMessage = "Required!");
    public string PhoneMobile { get; set; }

    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
    {

        if ((PhoneHome+PhoneWork+PhoneMobile).Length < 1)
        {
            yield return new ValidationResult("You should set up any phone number!", new [] { "ConfirmForm" });
        }
    }
}