Adding items to a List(of object

[!NoItAll]

I have some code that adds items to a List(of Object). It is behaving extremely bizarre!

Here's my original code

Dim BeaconStoryList as New List(Of My.StoryType)
Dim BeaconStory as New My.StoryType
Dim NewStories() as New Foriegn.StoryType = GetStories

For Each Story as Foriegn.StoryType in NewStories
     If Story.Type = My.BeaconType then
         BeaconStory.Title = Story.storyTitle
         BeaconStory.Body = Story.storyBody
         BeaconStory.Type = Story.storyType
         BeaconStoryList.Add(BeaconStory)
    End if
Next

This seamed pretty straight forward to me. There might be 20 stories, 5 of which were of type "My.BeaconT ype" and after the for each loop I would have a list(of collection of those 5 stories assigned to BeaconStoryList .
But...
After completing the loop every element in the collection would get the exact same values. Even though all 5 stories were different, all elements in the collection would get assigned the last values added to the end.
To stop this bizarre behavior I had to change the code to this

Dim BeaconStoryList as New List(Of My.StoryType)
Dim NewStories() as New Foriegn.StoryType = GetStories
Dim I as Integer = 0

For Each Story as Foriegn.StoryType in NewStories
     If Story.Type = My.BeaconType then
         BeaconStoryList.Add(New My.StoryType)
         BeaconStoryList(I).Title = Story.storyTitle
         BeaconStoryList(I).Body = Story.storyBody
         BeaconStoryList(I).Type = Story.storyType
         I +=1
    End if
Next

There must be something I do not understand that is going on. In the first code example I could step through the code with watch-points and actually see all of the indexes (0 through the current one) change value. For example: If I was on the first loop the BeaconStory.Tit le might be "Gravy". Then passing through the second loop the next story title would be "Chicken" so I would assume that BeaconStoryList (0).Title would be "Gravy" and BeaconStoryList (1).Title would be "Chicken".
But as soon as the code assigned "Chicken" to BeaconStory.Tit le, then BeaconStoryList (0).Title would also change to "Chicken".
With my second version of the code this did not happen.
It's as though it was placing pointers into the elements of the array rather than values. If that is the case, however, then why does my second version of the code work - I'm still passing in the same thing - aren't I?

!NoItAll

[tlhintoq]

In your Story class, are each of these properties set to static? If they are, then that is why you get the same values back.

[!NoItAll]

Ok - figured it out. Again - my own lack of experience surfaces like a bloated body in a lake...
ewwww!
My problem is that I did not understand how to properly create an array of my class. It's not as simple as:

Dim MyClassArray(20 ) as MyClass

Nor is it as easy as

Dim MyClassArray() as MyClass
Redim MyClassArray(20 )

At this point you do have 20 elements of the MyClass type, but there is nothing in them. Look at it in the debugger and you will see none of the individual elements from the MyClass appear. The next step is to fill in the elements of the class into each element of the array:

For I = 0 to 20
MyClassArray(I) = new MyClass
Next I

So that was PART of my problem. The other part of my problem is that the loop:

 
For Each Story as Foriegn.StoryType in NewStories
      If Story.Type = My.BeaconType then
          BeaconStory.Title = Story.storyTitle
          BeaconStory.Body = Story.storyBody
          BeaconStory.Type = Story.storyType
          BeaconStoryList.Add(BeaconStory)
     End if
 Next

Was actually just putting a pointer from each BeaconStory into the BeaconStoryList . Whenever I assigned a new value to any of the elements in BeaconStory then ALL elements inside of the BeaconStoryList would match.

To fix this all I needed to do was add one line of code within the loop

BeaconStory = New My.Storytype

So the code looks like this now:

 
For Each Story as Foriegn.StoryType in NewStories
      If Story.Type = My.BeaconType then
          BeaconStory = New My.StoryType
          BeaconStory.Title = Story.storyTitle
          BeaconStory.Body = Story.storyBody
          BeaconStory.Type = Story.storyType
          BeaconStoryList.Add(BeaconStory)
     End if
 Next

The addition of BeaconStory = New My.StoryType created a new copy of Beaconstory so that unique elements were created for addition into the BeaconStoryList .

This seemed confusing to me at first - but it appears that with created classes all you are ever passing in and out are pointers to the values (byRef) and not the actual data.

Still learning...

[!NoItAll]

Interesting tlhintoq - I don't specifically create anything as Static - I don't even know how to do that... Is it a default?

Here's an example of one of my classes

Public Class Story_type
    Private vBody As String
    Private vTitle As String
    Private vType As Integer = 0

    Public Property Body() As String
        Get
            Return vBody
        End Get
        Set(ByVal value As String)
            vBody = value
        End Set
    End Property

    Public Property Title() As String
        Get
            Return vTitle
        End Get
        Set(ByVal value As String)
            vTitle = value
        End Set
    End Property

    Public Property Type() As Integer
        Get
            Return vType
        End Get
        Set(ByVal value As Integer)
            vType = value
        End Set
    End Property

End Class

And then to set up the List(of I do this:

Public Class ArrayOfStory_type
    Inherits List(Of Story_type)
End Class

Is this cool - or weird?