Need help with SendMessage...

VB Code:

For i = 1 To ListView1.ListItems.Count
x = SendMessage(File1.hwnd, LB_FINDSTRING, -1, ByVal ListView1.ListItems.Item)
            If x = -1 Then 'item is NOT found in filelistbox
            strRemoved = ListView1.SelectedItem.Text

Well, here's what I've got to start with, and here's what I'm trying to do:

Compare each listitem in my listview to each item in my filelistbox. Then if the item in the listview is NOT found in the filelistbox, I want to log it to an array or something. After this is done, I will build an array ("removed ()") from my existing textfile, search the new array for any lines containing the items I logged to my "removed" array, and remove the lines from the array. Then I will build a new textfile with the updated array. Any help with this is appreciated. I can do the array searching, but I'm trying to figure out how to make an array that contains all of the items that weren't found.