Attaching MetaData class to ADO.NET Entity Data model classes

问题

I have a problem attaching metadata class to ADO.NET entity data model generated classes. According to the following links...

http://blogs.microsoft.co.il/blogs/gilf/archive/2011/01/20/adding-metadata-to-entities-in-the-data-model.aspx

http://msdn.microsoft.com/en-us/library/cc679243.aspx

http://goneale.com/2009/03/04/using-metadatatype-attribute-with-aspnet-mvc-xval-validation-framework/

http://davidhayden.com/blog/dave/archive/2008/01/06/ASPNETDynamicDataTutorialBuddyMetadataProviderCustomMetadataProviders.aspx

http://davidhayden.com/blog/dave/archive/2008/05/15/DynamicDataWebsitesScaffoldTableScaffoldColumnAttributes.aspx

I created a metadata class to add some Attributes to properties. I could add this attributes to properties in generated classes and It works but I wanted to avoid loosing this attributes every time I have to update and recreate my ADO.NET entity data model.

My question is, what am I doing wrong ? Why in runtime properties does not have my custom attributes ?

This is a part of generated data class

[EdmEntityTypeAttribute(NamespaceName="HelpMeHowModel", Name="Article")]
[Serializable()]
[DataContractAttribute(IsReference=true)]
[MetadataType(typeof(ArticleMetaData))]
public partial class Article : EntityObject
{
    #region Primitive Properties

    /// <summary>
    /// No Metadata Documentation available.
    /// </summary>
    [EdmScalarPropertyAttribute(EntityKeyProperty=false, IsNullable=false)]
    [DataMemberAttribute()]
    public global::System.Boolean IsPublished
    {
        get
        {
            return _IsPublished;
        }
        set
        {
            OnIsPublishedChanging(value);
            ReportPropertyChanging("IsPublished");
            _IsPublished = StructuralObject.SetValidValue(value);
            ReportPropertyChanged("IsPublished");
            OnIsPublishedChanged();
        }
    }
    private global::System.Boolean _IsPublished;
    partial void OnIsPublishedChanging(global::System.Boolean value);
    partial void OnIsPublishedChanged();

...

.. and this is my metadata class

public class ArticleMetaData
{
    #region Primitive Properties

    [BoolFunction(BoolFunction.ThreeStateRadioButton)]
    public global::System.Boolean IsPublished { get; set; }

回答1:

For everybody looking for the solution for the same problem...

Adding custom attributes to partial MetadataType class is possible and it works but there is a little problem.

Using

PropertyInfo pi;

pi.GetCustomAttributes(...) 

will get the Attributes from the main class only and not from the class used as MetadataType.

Based on solution explained here

Attribute.IsDefined doesn't see attributes applied with MetadataType class

I created two extension methods for PropertyInfo class to get all attributes.

namespace FAIN.Framework.Commons
{
    public static class PropertyInfoEx
    {
        public static object[] GetAllCustomAttributes(this PropertyInfo pi, bool inherit)
        {
            return GetAllCustomAttributes(pi, null, inherit);
        }
        /// <summary>
        /// Get Custom Attributes + attributes added in MetadataType
        /// </summary>
        /// <param name="pi"></param>
        /// <param name="attributeType"></param>
        /// <param name="inherit"></param>
        /// <returns></returns>
        public static object[] GetAllCustomAttributes(this PropertyInfo pi, Type attributeType, bool inherit)
        {
            if (pi == null) return null;
            List<object> allAttributes = new List<object>();
            object[] attributes = null;
            if (attributeType != null)
            {
                attributes = pi.GetCustomAttributes(attributeType, inherit);
            }
            else
            {
                attributes = pi.GetCustomAttributes(inherit);
            }
            allAttributes.AddRange(attributes);

            // search all the Metadata of the class declaring the property to get all CustomAttributes if there are any
            MetadataTypeAttribute[] metadataTypes = pi.DeclaringType.GetCustomAttributes(typeof(MetadataTypeAttribute), true).OfType<MetadataTypeAttribute>().ToArray();
            foreach (MetadataTypeAttribute metadata in metadataTypes)
            {

                if (metadata != null)
                {
                    PropertyInfo[] properties = metadata.MetadataClassType.GetProperties();
                    PropertyInfo propertyInfo = properties.Where(p => p.Name == pi.Name).FirstOrDefault();
                    if (propertyInfo != null)
                    {
                        if (attributeType != null)
                        {
                            attributes = propertyInfo.GetCustomAttributes(attributeType, inherit);
                        }
                        else
                        {
                            attributes = propertyInfo.GetCustomAttributes(inherit);
                        }
                        allAttributes.AddRange(attributes);
                    }
                }
            }

            return allAttributes.ToArray();
        }
    }
}

来源：https://stackoverflow.com/questions/7868230/attaching-metadata-class-to-ado-net-entity-data-model-classes