ADO Architecture

Use the ADO Connection object to bind to a particular public or private store, handle transactions, and share across Record and Recordset objects to avoid continually rebinding to stores. For example:

Dim Conn as New ADODB.Connection
Conn.Provider = "ExOLEDB.DataSource"
Conn.Open RootFolderURL
Conn.BeginTrans
Rec.Open ItemURL, Conn, adModeReadWrite
' ..
Conn.CommitTrans
' ..
Conn.Close
Rec.Close
Set Conn = Nothing
Set Rec = Nothing

Placing Connection object references in ASP Session or Application objects and reusing this connection from one ASP page to another is ideal for optimal server-side performance.

You need a separate Connection object to bind to items in a different Exchange store mailbox store or public store. To avoid poor performance, you should reuse these Connection objects whenever possible. For example:

Dim Conn1 as New ADODB.Connection
Dim Conn2 as New ADODB.Connection
Dim Rec as New Record

' Assume /vroot1 is mapped to one public store and
'        /vroot2 is mapped to another.
Conn1.Provider="exoledb.datasource"
Conn1.Open "https://servername/vroot1"

Conn2.Provider="exoledb.datasource"
Conn2.Open "https://servername/vroot2"

Rec.Open "https://servername/vroot1/folder1/item.eml", Conn1, adModeReadWrite
Rec.Close
'...
Rec.Open "https://servername/vroot_2/folder2/item2.eml", Conn2, adModeReadWrite

'... Conn1.Close Conn2.Close Rec.Close Set Conn1 = Nothing Set Conn2 = Nothing Set Rec = Nothing

Use the ADO Fields collection and the ADO Field object to access an item's properties. For example:

Dim Rec as New ADODB.Record
Dim Conn as New ADODB.Connection
Dim Flds as ADODB.Fields
Dim Fld as ADODB.Field
Dim Url As String

Url = "https://server/public/test/item.eml"

Conn.Provider = "ExOLEDB.DataSource"
Conn.Open Url

Rec.Open Url, Conn, adModeReadWrite
Set Flds = Rec.Fields
For Each Fld in Flds
  '...
Next Fld
' ...
Conn.Close
Rec.Close
Set Conn = Nothing
Set Rec = Nothing

Use the Record object to access any item in the Exchange store. You have full access to the item's set of properties and its associated stream. For example:

Dim Rec As New ADODB.Record
Dim Conn as New ADODB.Connection
Dim Stm as ADODB.Stream
Conn.Provider = "ExOLEDB.DataSource"
Conn.Open "https://server/folder"
Rec.Open "https://server/folder/item.txt", Conn
Set Stm = Rec.Fields(adDefaultStream).Value
'...
Conn.Close
Rec.Close
Set Conn = Nothing
Set Rec = Nothing

Use the Recordset object to issue Structured Query Language (SQL) SELECT commands in folders. For example:

Dim Conn as New ADODB.Connection
Dim Rs as New ADODB.Recordset
Conn.Provider = "ExOLEDB.DataSource"
Conn.Open RootFolderURL

Set Rs.ActiveConnection = Conn
"select ""DAV:displayname"" " _
& "from scope('shallow traversal of ""URL""')" _
& "Where ""DAV:ishidden"" = False"

'...
Conn.Close
Rs.Close
Set Conn = Nothing
Set Rs = Nothing

Use the ADO Stream object to access an item's stream. For example:

Dim Stm As ADODB.Stream
Dim Rec as New ADODB.Record
Dim Conn as New ADODB.Connection
Dim Stm2 as New ADODB.Stream
Dim Url As String

Url = "https://server/public/item.txt"

Conn.Provider = "ExOLEDB.DataSource"
Conn.Open Url
Rec.Open Url, Conn
Set Stm = Rec.Fields(adDefaultStream).Value
' Or, alternately
Stm2.Open Rec, adModeRead, adOpenStreamFromRecord

'...
Conn.Close
Rec.Close
Stm.Close
Stm2.Close
Set Conn = Nothing
Set Rec = Nothing
Set Stm = Nothing
Set Stm2 = Nothing