在自定义数据批注中访问依赖属性的简单方法 [英] Simple way of accessing dependent property inside custom data annotation

问题描述

我的 DomainRegistry 模型具有以下属性:

I have the following properties on my DomainRegistry model:

    [Domain("Extension")]
    public string Name { get; set; }

    [Required(ErrorMessage = "Select extension")]
    public string Extension { get; set; }

请确保这是我的自定义数据注释，并且我已经尝试过 IsValid 方法上的所有内容来访问扩展属性内的值.

Domain it's my custom data annotation and I've tryed everything on my IsValid method to access the value inside extension property.

自定义数据注释中包含以下内容:

I have the following in my custom data annotation:

[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class DomainAttribute : ValidationAttribute
{
    public string ExtensionProperty { get; set; }

    public DominioAttribute(string property)
    {
        ExtensionProperty = property;
    }

    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(value);
        var extension = (string) properties.Find(Propriedade, true).GetValue(value);
        if (extension == null) return new ValidationResult("Extension shouldn't be null");
        return null;
    }

我似乎无法从 IsValid 方法中的扩展获取值.有人对如何做到这一点有任何建议吗?另外，我需要将扩展​​名作为字符串值.

I can't seem to get the value from extension inside IsValid method. Anyone have any tip on how to do that? Also I need to get extension as a string value.

推荐答案

尝试一下:

protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        var containerType = validationContext.ObjectInstance.GetType();
        var field = containerType.GetProperty("Extension");

        if (field != null)
        {
            var extensionValue = field.GetValue(validationContext.ObjectInstance, null);

            return extensionValue != null ? ValidationResult.Success : new ValidationResult("Extension shouldn't be null", new[] { validationContext.MemberName });
        }

        return ValidationResult.Success;
    }

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