在C＃类之间传递值时缺少对象值

Question

I have this method in the static class "ObjectMapper":

As we can see, the method has an object "dataReader" with some items ([0]). But... When I invoke this method:

The passed parameter is losing this record. Even changing the method "DataReaderToObjectList" from "public static" to "public", the value is losing this data. When my object has two or more records, it is being passed, but "killing" the first record. If I do it in the "classic" way, I can manipulate the dataReader correctly. But I need this method working, once it is used in several places in the application.

Answer 1

In SelectAll() you call .Read()
Boom first record gone
You do NOTHING with that record

In DataReaderToObject
You call .Read()
Boom you are on the second record

Answer 2

Note that you can only enumerate the contents of an SqlDataReader object one time. This includes enumerating them in the Results View preview window. The data is being lost in this specific instance because you are enumerating them in the debugger, which exhausts the reader, then stepping into the function with an exhausted reader

I think there is also a more fundamental error in your code. You are calling the Read method twice on the same instance without actually enumerating any of the data that resulted from the first read. You can fix this by removing the Read call in the SelectAll method

Answer 3

I found an alternative solution for this problem, that solved (at least for now):

In the item 1, I declared a generic object that gets the attributes and values from dataReader and passed as a parameter (doing an explicit cast, as we can see) to a new method that gets this object as SqlDataReader, as shown in item 2 of image below.

This new method is placed in the same static class ObjectMapper, but oddly I'm being able to pass my object as parameter without losing any data. @Blam, your theory makes sense, but didn't worked here in this case.