实体框架多对多通用更新

本文关键字：更新 框架 实体 | 更新日期: 2023-09-27 18:27:24

我正在尝试使用EF6实现一个通用的多对多更新方法。每次我尝试更新导航属性时，我都会得到一个异常：

"违反PRIMARY KEY约束'PK_dbo.Classes'。无法插入对象"dbo.Classes"中存在重复键。重复键值为（698d5483-eb48-4d7e-84e7-a9f95a243d3d）。''''r''n声明已经终止。"

我该怎么修？

public void Update(T entity, params Expression<Func<T, IEnumerable>>[] navProps)
{
    using (var context = new Context())
    {
        T foundEntity = context.Set<T>().Find(entity.Id);
        var entry = context.Entry(foundEntity);
        entry.CurrentValues.SetValues(entity);
        foreach (var prop in navProps)
        {
            string memberName;
            var member = prop.Body as MemberExpression;
            if (member != null)
            {
                memberName = member.Member.Name;
            }
            else
            {
                throw new Exception();
            }
            var collection = entry.Collection(memberName);
            collection.Load();
            collection.CurrentValue = typeof(T).GetProperty(memberName).GetValue(entity);
        }
        context.SaveChanges();
    }
}

实体框架多对多通用更新

最后，我找到了一个通用多对多更新的解决方案

 public void Update(Guid id, T record)
        {
            using (var context = new FortisDataStoreContext(_client, _user))
            {
                var set = context.Set<T>().AsQueryable();
                foreach (var x in GetNavigationProperties(context, record))
                {
                    foreach (var xx in x.PropertyType.GetGenericArguments())
                    {
                        set = set.Include(x.Name);
                    }
                }
                var entry = set.FirstOrDefault(x => x.Id == id && x.IsClosed == false);
                context.Entry(entry).CurrentValues.SetValues(record);
                foreach (var x in GetNavigationProperties(context, record))
                {
                    if(x.PropertyType.GetGenericArguments().Count() > 0)
                    {
                        var genericType = x.PropertyType.GenericTypeArguments[0];
                        var newValues = (IList)x.GetValue(record, null) ?? new object[0];
                        var genericList = CreateList(genericType);
                        foreach (var item in newValues)
                        {
                            var ident = item.GetType().GetProperty("Id").GetValue(item, null);
                            var obj = context.Set(genericType).Find(ident);
                            genericList.Add(obj);
                        }
                        context.Entry(entry).Collection(x.Name).CurrentValue = genericList;
                    }
                }
                context.SaveChanges();
            }
        }
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