Overview
This Access 2000 How To's article explains how to load data into a treeview control. Nodes in a treeview have a parent key and a child key. In this
example, the first level of nodes contains process ids and titles. In the second level, Activities represent dependant child nodes. One or more activies are associated as children to the a process.
When the user clicks on a node, its key is parsed and the contents determine the type of node: process or activity. Depending on the type of node, a filter criteria is applied to a join between the process and activity table.
Building the Control
Option Compare Database
Option Explicit
Private Sub FindTreeCtrl_NodeClick(ByVal Node As Object)
'AT
Dim iOffset
Dim iLength
Dim sId
Dim i
Dim ch
iOffset = InStr(Node.Key, "AT")
If (iOffset > 0) Then
iLength = Len(Node.Key)
sId = Mid(Node.Key, iOffset + 2, iLength - iOffset + 1)
'Filter for a task
Filter = "Id=" & sId
FilterOn = True
Else
iOffset = InStr(Node.Key, "P")
'Filter for a process
If iOffset > 0 Then
iLength = Len(Node.Key)
For i = iOffset To iLength
ch = Mid(Node.Key, iOffset + i, 1)
If IsNumeric(ch) = True Then
sId = sId & ch
Else
Exit For
End If
Next
Filter = "ProcessId=" & sId
FilterOn = True
End If
End If
End Sub
Private Sub Form_Load()
Dim objNode As Node
Dim dbs As Object
Dim rs As Object
Dim rs2 As Object
Dim sProcessId As String
Dim sProcessName As String
Dim sActivityId As String
Dim sActivityTitle As String
Set dbs = CurrentDb
Set rs = dbs.Openrecordset("select * from processes")
With FindTreeCtrl
.Nodes.Clear
Set objNode = .Nodes.Add(, , "root", "Activities")
objNode.Expanded = True
Set objNode = .Nodes.Add("root", tvwChild, "TT", "Processes")
objNode.Expanded = True
Do While Not rs.EOF
sProcessId = "P" & rs("processid")
sProcessName = "" & rs("processName")
Set objNode = .Nodes.Add("TT", tvwChild, sProcessId, sProcessName)
Set rs2 = dbs.Openrecordset("select * from activities where processid=" & rs("processid"))
Do While Not rs2.EOF
sActivityId = sProcessId & "AT" & rs2("id")
sActivityTitle = "" & rs2("activitytitle")
Call .Nodes.Add(sProcessId, tvwChild, sActivityId, sActivityTitle)
rs2.MoveNext
Loop
rs.MoveNext
Loop
End With
If Not rs Is Nothing Then
rs.Close
End If
Set rs = Nothing
If Not rs2 Is Nothing Then
rs2.Close
End If
Set rs2 = Nothing
End Sub
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