未使用 MetadataType 加载元数据

Metadata were not loaded using MetadataType(未使用 MetadataType 加载元数据)

问题描述

我有一些关于 元数据类型.我有使用 LinqToSQL 从 MS SQL Server 访问数据的 DLL 帮助程序项目.我还需要为生成的类 ClientInfoView 添加元数据.我已经按照以下方式完成了:

I've got a some problem/question about MetadataType. I've got DLL helper-project for data access from MS SQL Server using LinqToSQL. I've also need to add a metadata for a generated class ClientInfoView. I've done it following way:

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel;

namespace DataAPI.LINQToSQL
{
    [MetadataType(typeof(ClientInfoViewMetaData))]
    public partial class ClientInfoView
    {
        internal sealed class ClientInfoViewMetaData
        {
            [Category("Main Data"), DisplayName("Client ID")]
            public int ID { get; set; }

            [Category("Main Data"), DisplayName("Login")]
            public string Login { get; set; }

            ...
        }
    }
}

但是当我在运行时检查属性时，我发现 ClientInfoView 没有任何属性.

But when I checked the attributes in runtime, I've found that ClientInfoView hasn't got any attributes.

你能帮我找出错误吗?

推荐答案

要给出部分答案，您可以检查 ClientInfoView 是否具有属性.一些对我有用的小演示.仍在试图找出为什么我无法访问 ClientInfoViewMetaData 单个属性中的这些属性

To give some part of the answer , you can check ClientInfoView has got attributes. Some small demo that worked for me. Still trying to find why I can't access those attributes in ClientInfoViewMetaData individual properties

    static void Main(string[] args)
    {
        TypeDescriptor.AddProviderTransparent(
        new AssociatedMetadataTypeTypeDescriptionProvider(typeof(ClientInfoView), typeof(ClientInfoViewMetaData)), typeof(ClientInfoView));
        ClientInfoView cv1 = new ClientInfoView() { ID = 1 };
        var df = cv1.GetType().GetCustomAttributes(true);
        var dfd = cv1.ID.GetType().GetCustomAttributes(typeof(DisplayNameAttribute), true);
        var context = new ValidationContext(cv1, null, null);
        var results = new List<ValidationResult>();
        var isValid = Validator.TryValidateObject( cv1,context, results, true);
    }
}

    [MetadataType(typeof(ClientInfoViewMetaData))]
    public partial class ClientInfoView
    {
        public int ID { get; set; }
        public string Login { get; set; }
    }

public class ClientInfoViewMetaData
{        
    [Required]
    [Category("Main Data"), DisplayName("Client ID")]
    public int ID { get; set; }

    [Required]
    [Category("Main Data"), DisplayName("Login")]
    public string Login { get; set; }

}

这篇关于未使用 MetadataType 加载元数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！