c# - c# 如何添加基于布尔值的自定义验证

Question

在这里我有一个类

Public Class Employee
{
       [Required]
        public string FName { get; set; }
        [Required]
        public bool Married { get; set; }

        public string WifeName { get; set; }
        public string Wife_dOB { get; set; }

}

此处 WifeName 和 Wife_Dob 仅在已婚为真时才需要请帮助我如何解决此问题我在这里使用 MVC

标签： c#customvalidator

Answer 1

您可以使用自定义验证属性。

您可以在下面看到我前几次使用的解决方案：

/// <summary>
/// Provides conditional validation based on related property value.
/// </summary>
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
public sealed class RequiredIfAttribute : ValidationAttribute
{
#region Properties

/// <summary>
/// Gets or sets the other property name that will be used during validation.
/// </summary>
/// <value>
/// The other property name.
/// </value>
public string OtherProperty { get; private set; }

/// <summary>
/// Gets or sets the display name of the other property.
/// </summary>
/// <value>
/// The display name of the other property.
/// </value>
public string OtherPropertyDisplayName { get; set; }

/// <summary>
/// Gets or sets the other property value that will be relevant for validation.
/// </summary>
/// <value>
/// The other property value.
/// </value>
public object OtherPropertyValue { get; private set; }

/// <summary>
/// Gets or sets a value indicating whether other property's value should match or differ from provided other property's value (default is <c>false</c>).
/// </summary>
/// <value>
///   <c>true</c> if other property's value validation should be inverted; otherwise, <c>false</c>.
/// </value>
/// <remarks>
/// How this works
/// - true: validated property is required when other property doesn't equal provided value
/// - false: validated property is required when other property matches provided value
/// </remarks>
public bool IsInverted { get; set; }

/// <summary>
/// Gets a value that indicates whether the attribute requires validation context.
/// </summary>
/// <returns><c>true</c> if the attribute requires validation context; otherwise, <c>false</c>.</returns>
public override bool RequiresValidationContext
{
    get { return true; }
}

#endregion

#region Constructor

/// <summary>
/// Initializes a new instance of the <see cref="RequiredIfAttribute"/> class.
/// </summary>
/// <param name="otherProperty">The other property.</param>
/// <param name="otherPropertyValue">The other property value.</param>
public RequiredIfAttribute(string otherProperty, object otherPropertyValue)
    : base("'{0}' is required because '{1}' has a value {3}'{2}'.")
{
    this.OtherProperty = otherProperty;
    this.OtherPropertyValue = otherPropertyValue;
    this.IsInverted = false;
}

#endregion

/// <summary>
/// Applies formatting to an error message, based on the data field where the error occurred.
/// </summary>
/// <param name="name">The name to include in the formatted message.</param>
/// <returns>
/// An instance of the formatted error message.
/// </returns>
public override string FormatErrorMessage(string name)
{
    return string.Format(
        CultureInfo.CurrentCulture,
        base.ErrorMessageString,
        name,
        this.OtherPropertyDisplayName ?? this.OtherProperty,
        this.OtherPropertyValue,
        this.IsInverted ? "other than " : "of ");
}

/// <summary>
/// Validates the specified value with respect to the current validation attribute.
/// </summary>
/// <param name="value">The value to validate.</param>
/// <param name="validationContext">The context information about the validation operation.</param>
/// <returns>
/// An instance of the <see cref="T:System.ComponentModel.DataAnnotations.ValidationResult" /> class.
/// </returns>
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
    if (validationContext == null)
    {
        throw new ArgumentNullException("validationContext");
    }

    PropertyInfo otherProperty = validationContext.ObjectType.GetProperty(this.OtherProperty);
    if (otherProperty == null)
    {
        return new ValidationResult(
            string.Format(CultureInfo.CurrentCulture, "Could not find a property named '{0}'.", this.OtherProperty));
    }

    object otherValue = otherProperty.GetValue(validationContext.ObjectInstance);

    // check if this value is actually required and validate it
    if (!this.IsInverted && object.Equals(otherValue, this.OtherPropertyValue) ||
        this.IsInverted && !object.Equals(otherValue, this.OtherPropertyValue))
    {
        if (value == null)
        {
            return new ValidationResult(this.FormatErrorMessage(validationContext.DisplayName));
        }

        // additional check for strings so they're not empty
        string val = value as string;
        if (val != null && val.Trim().Length == 0)
        {
            return new ValidationResult(this.FormatErrorMessage(validationContext.DisplayName));
        }
    }

    return ValidationResult.Success;
}