System.ComponentModel.dataAnnotations.CustomValidation

Question

有没有人能帮我做一下System.ComponentModel.dataAnnotations.CustomValidation.的全面展示

这是我的头像

我有EventMetadata & EventAttributeMetadata课程。在EventMetadata中，我有Startdate和Enddate属性&在EventAttributeMetadata中，我有HoldOutdate属性。我想对HoldOutdate属性执行以下验证。“延迟日期应在事件开始日期和结束日期之间”。这应该使用System.ComponentModel.dataAnnotations命名空间。

Answer 1

此示例位于创建一个非空的默认mvc应用程序时创建的AccountModel中，并根据需要对其进行修改和使用。

[AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
public class PropertiesMustMatchAttribute : ValidationAttribute
{
    private const string _defaultErrorMessage = "'{0}' and '{1}' do not match.";
    private readonly object _typeId = new object();

    public PropertiesMustMatchAttribute(string originalProperty, string confirmProperty)
        : base(_defaultErrorMessage)
    {
        OriginalProperty = originalProperty;
        ConfirmProperty = confirmProperty;
    }

    public string ConfirmProperty { get; private set; }
    public string OriginalProperty { get; private set; }

    public override object TypeId
    {
        get
        {
            return _typeId;
        }
    }

    public override string FormatErrorMessage(string name)
    {
        return String.Format(CultureInfo.CurrentUICulture, ErrorMessageString,
            OriginalProperty, ConfirmProperty);
    }

    public override bool IsValid(object value)
    {
        PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(value);
        object originalValue = properties.Find(OriginalProperty, true /* ignoreCase */).GetValue(value);
        object confirmValue = properties.Find(ConfirmProperty, true /* ignoreCase */).GetValue(value);
        return Object.Equals(originalValue, confirmValue);
    }
}