从对象中提取值 [英] extract values out of object

问题描述

你好，亲爱的读者。

我试图找出EF数据库对象之间的关系

这是完成这项任务的功能：

Hello, dear reader.
I am trying to find out relations between EF Database objects
This is the function to fulfill that task:

private object getCollectionReference(object EFtable, string navigationproperty)
        {
            object collectionreference = new object();
            //now try to query the table
            try
            {
                DbEntityEntry db = ce.Entry(EFtable);
                //query collections of referenced tables
                collectionreference = db
                    .Collection(navigationproperty)
                    .Query()
                    .AsQueryable();
            }
            catch (Exception e)
            {
                //query single referenced table
                DbEntityEntry db = ce.Entry(EFtable);
                collectionreference = db
                    .Reference(navigationproperty)
                    .Query()
                    .AsQueryable();
            }
            return collectionreference;
        }

在铸造之前效果很好... :-(

对象EFtable可以是我们数据库中的任何实体。

是否有机会将其重新投入所需的EF对象以进行进一步处理？

我读过关于用Reflections解决问题的几十篇文章，这是我到目前为止所做的：

That works pretty well until it comes to casting... :-(
The object EFtable can be any Entity in our database.
Is there any opportunity to cast it back into the desired "EF Object" for further processing it?
I read dozens of articles about solving that with Reflections, here is what I´ve done so far:

     //get the referenced table[s]
object referenceLogAction4 = getCollectionReference(us, "Data_Subjects");
     //get the type
Type ref4 = referenceLogAction4.GetType();
  //load all properties
IList<PropertyInfo> pops = new List<PropertyInfo>(ref4.GetProperties());
List<object> lobj = new List<object>();
foreach (PropertyInfo pop in pops)
{
      object popvalue = pop.GetValue(referenceLogAction4, null);
      lobj.Add(popvalue);
}
//try loading fields
IList<FieldInfo> fies = new List<FieldInfo>(ref4.GetFields());
List<object> lfie = new List<object>();
foreach (FieldInfo fie in fies)
{
    object fiesvalue = fie.GetValue(referenceLogAction4);
    lfie.Add(fiesvalue);
    
}

Propertyinfo和Fieldinfo似乎都不是我想要的; Fieldinfo部分返回零Fieldinfos，Propertyinfo值为：



it

转换后的SQL语句

[System.Data.Entity.Core.Objects.ObjectContext]

AppendOnly

true

[System.Data.Entity.Core。 Objects.ObjectParameterCollection]

true



我觉得这些是对象类型的标准属性...



我也尝试通过

neither Propertyinfo nor Fieldinfo seems to be what I want; the Fieldinfo part returns zero Fieldinfos, the Propertyinfo values are:

"it"
"Transformed SQL Statement"
[System.Data.Entity.Core.Objects.ObjectContext]
AppendOnly
true
[System.Data.Entity.Core.Objects.ObjectParameterCollection]
true

Seems to me that these are the standard properties of type object...

I also tried casting it via

ToType<T>(this object obj, T type) where T : class
...

但无济于事...



所以，简而言之：



有谁知道，我需要做什么才能将对象转换为我想要的EF实体对象？



非常感谢，

Clodetta

but to no avail...

so, to put long things short:

does anybody know, what I need to do to cast the object to my desired EF entity object?

Thanks a lot in advance,
Clodetta

推荐答案

大家好。

我终于找到了解决方案：jig：

Hi, everybody.
I finally found a solution :jig:

object referenceLogAction4 = getCollectionReference(us, "Data_Subjects");

现在可以使用此片段转换referenceLogAction4：

referenceLogAction4 can now be converted using this snippet:

List<Data_Subjects> dsubj = (((System.Data.Entity.Core.Objects.ObjectQuery<Data_Subjects>)referenceLogAction4).ToList());

etvoilá，我现在可以迭代通过所有退回的表格参考....



亲切的问候，

Clodetta



PS：我如何将这个问题标记为已解决？



PPS：它将自己标记为解决方案......

et voilá, I now can iterate through all returned table references....

kind regards,
Clodetta

PS: How can I mark this question as solved?

PPS: It marked itself as solution...

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