从实体框架中的ObjectStateEntry获取所有键及其值

Question

为了审计日志记录的目的，我覆盖了EF 4.1数据库优先方法中的SaveChanges()方法。

我有所有的ObjectStateEntry对象，我想知道是否可以从每个ObjectStateEntry中获取所有键及其值。

   IEnumerable<ObjectStateEntry> changes = this.ObjectStateManager.GetObjectStateEntries(EntityState.Added | EntityState.Deleted | EntityState.Modified);
    foreach (ObjectStateEntry stateEntryEntity in changes)
    {
        if (!stateEntryEntity.IsRelationship &&
                stateEntryEntity.Entity != null &&
                    !(stateEntryEntity.Entity is DBAudit))
        {
          list<object , object> KeyValues = GetAllKeyValues(stateEntryEntity );
          //Do log all keyvalues
        }
    }

Answer 1

我还没有测试过它，但像这样的东西应该可以工作：

private Dictionary<string, object> GetAllKeyValues(ObjectStateEntry entry)
{
    var keyValues = new Dictionary<string, object>();
    var currentValues = entry.CurrentValues;
    for (int i = 0; i < currentValues.FieldCount; i++)
    {
        keyValues.Add(currentValues.GetName(i), currentValues.GetValue(i));
    }
    return keyValues;
}

Answer 2

尝试使用ObjectStateEntry.EntityKey和EntityKey.EntityKeyValues:

var keyValues = stateEntityEntry.EntityKey.EntityKeyValues;

返回EntityKeyMember的数组。然后可以使用Key和Value属性，它们分别返回string和object。

Answer 3

这是我的扩展方法形式的解决方案。

public static class ExtensionMethods
{
    public static IReadOnlyDictionary<string, object> GetKeyValues(this ObjectStateEntry instance)
    {
        var keyMemberNames = instance
            .EntitySet
            .ElementType
            .KeyMembers
            .Select(x => x.Name)
            .ToList();
        var currentValues = instance.CurrentValues;
        var result = new Dictionary<string, object>();
        for (var i = 0; i < currentValues.FieldCount; i++)
        {
            var name = currentValues.GetName(i);
            if (!keyMemberNames.Contains(name))
                continue;
            var value = currentValues.GetValue(i);
            result.Add(name, value);
        }
        return result;
    }
    public static IReadOnlyDictionary<string, object> GetValues(this ObjectStateEntry instance)
    {
        var currentValues = instance.CurrentValues;
        var result = new Dictionary<string, object>();
        for (var i = 0; i < currentValues.FieldCount; i++)
        {
            var name = currentValues.GetName(i);
            var value = currentValues.GetValue(i);
            result.Add(name, value);
        }
        return result;
    }
}