Searching with ActiveX Data Objects (ADO)

The ActiveX Data Object (ADO) model consists of objects listed in the following table.

For ADO to communicate with ADSI, there must be, at least, two ADO objects: Connection and RecordSet. These ADO objects serve to authenticate users and enumerate results, respectively. Typically, you will also use a Command object to maintain an active connection, specify query parameters, such as page size and search scope, and perform a query. For more information about the search filter syntax, see Search Filter Syntax.

The Connection object loads the OLE DB provider, and validates user credentials. In Visual Basic, call the CreateObject function with "ADODB.Connection" to create an instance of a Connection object, and then set the Provider property of the Connection object to "ADsDSOObject". "ADODB.Connection" is the ProgID of the Connection object and "ADsDSOObject" is the name of the OLE DB provider in ADSI. If no credentials are specified, the credentials of the currently logged on user are used.

The following code example shows how to create an instance of a Connection object.

Set con = CreateObject("ADODB.Connection")
con.Provider = "ADsDSOObject"

The following code example shows how to create an instance of a Connection object.

<%
Set con = Server.CreateObject("ADODB.Connection")
con.Provider = "ADsDSOObject"
%>

The following code example shows how to create an instance of a Connection object. Be aware that you must include the ADO type library (msadoXX.dll) as one of the references in the Visual Basic project.

Dim Con As New Connection
con.Provider = "ADsDSOObject"

Specify user authentication data by setting the properties of the Connection object. The following table lists ADSI-supported user-authentication properties.

The following code example shows how the properties are set before creating the Command object.

Set oConnect = CreateObject("ADODB.Connection")
oConnect.Provider = "ADsDSOObject"
oConnect.Properties("User ID") = stUser
oConnect.Properties("Password") = stPass
oConnect.Properties("Encrypt Password") = True
oConnect.Open "DS Query", stUser, stPass

The second ADO object is the Command object. The ProgID of the Command object is "ADODB.Command". This object enables you to issue query statements and other commands to ADSI using the active connection. The Command object uses its ActiveConnection property to maintain an active connection. It also maintains the CommandText property to hold query statements issued by a user. The query statements are expressed in either the SQL dialect or the LDAP dialect.

The following code examples show how to create a Command object.

Set command = CreateObject("ADODB.Command")
Set command.ActiveConnection = oConnect
command.CommandText = 
"SELECT AdsPath, cn FROM 'LDAP://DC=Fabrikam,DC=com' WHERE objectClass = '*'"

In the following code example, include ADO type library (msadoXX.dll) as one of the references.

Dim command As New Command
Set command.ActiveConnection = oConnect
command.CommandText = "<LDAP://DC=Fabrikam,DC=com>;(objectClass=*);AdsPath, cn; subTree"

Search options for the Command object are specified by setting the Properties property. The following table lists acceptable named properties for Properties.

The following code example shows how to set search options.

Const ADS_SCOPE_ONELEVEL = 1
Const ADS_CHASE_REFERRALS_EXTERNAL = &H40

Dim Com As New Command
 
Com.Properties("Page Size") = 999
Com.Properties("Timeout") = 30     ' Seconds
Com.Properties("searchscope") = ADS_SCOPE_ONELEVEL
Com.Properties("Chase referrals") = ADS_CHASE_REFERRALS_EXTERNAL
Com.Properties("Cache Results") = False     ' Do not cache the result set.

The third ADO object is RecordSet. You obtain this object when you invoke the Execute method on a Command object. The primary function of the RecordSet object is to enumerate the result set and obtain the data. The result set can contain values for attributes that have both single or multiple values. Getting a single-valued attribute is simple, similar to getting the column value in the relational database, for example:

Fields('name').Value

Getting an attribute with multiple values, however, is more challenging. In this case, the Field.Value is an array and you must check the lower and upper bound of the array, as shown in the following code example.

Set rs = Com.Execute
 
For i = 0 To rs.Fields.Count - 1
    Debug.Print rs.Fields(i).Name, rs.Fields(i).Type
Next i
 
'--------------------------
' Navigate the record set.
'--------------------------
rs.MoveFirst
lstResult.Clear      ' Clear the user interface.
While Not rs.EOF
For i = 0 To rs.Fields.Count - 1
    ' For Multi Value attribute
    If rs.Fields(i).Type = adVariant And Not (IsNull(rs.Fields(i).Value)) Then
        Debug.Print rs.Fields(i).Name, " = "
        For j = LBound(rs.Fields(i).Value) To UBound(rs.Fields(i).Value)
            Debug.Print rs.Fields(i).Value(j), " # "
            lstResult.AddItem rs.Fields(i).Value(j)
        Next j
    Else
        ' For Single Value attribute.
         Debug.Print rs.Fields(i).Name, " = ", rs.Fields(i).Value
         lstResult.AddItem rs.Fields(i).Value
    End If
Next i
rs.MoveNext
Wend

The following code example disables the user accounts on an LDAP server.

Dim X as IADs
Dim con As New Connection, rs As New Recordset
Dim MyUser As IADsUser
 
con.Provider = "ADsDSOObject"
con.Open "Active Directory Provider", "CN=Test,CN=Users,DC=Fabrikam,DC=COM,O=INTERNET", "Password"
Set rs = con.Execute("<LDAP://MyMachine/DC=MyDomain,DC=Fabrikam,DC=com>;(objectClass=User);ADsPath;onelevel")
 
While Not rs.EOF
    ' Bind to the object to make changes 
    ' to it because ADO is currently read-only.
    MyUser = GetObject(rs.Fields(0).Value)
    MyUser.AccountDisabled = True
    MyUser.SetInfo
    rs.MoveNext
Wend

For more information about the ADO object model, see Microsoft ActiveX Data Objects.

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Build date: 10/26/2012