Comments by Jake Robert (Top 12 by date)

Gonna try it maybe tomorrow. My head is already spinning. I will update you as soon as I test your solution.

Thanks :)

Here it is

Dim CompQuery As String = "SELECT * FROM Company WHERE CompanyName = '" & txtCompName.Text & "' AND AssociationID = " & cmbUnderAssoc.SelectedValue & " "

I also updated my question for a better view.

I use the cell mouseclick to get the displayed data in the datagridview.
So when I single-clicked a dataset in the datagridview, it will transfer the value of a single row into the textbox.

But when I remove the parenthesis it pops out an error like this:
Syntax error (missing operator) in query expression 'Sector.SectorID=Association.SectorID INNER JOIN Company ON Association.AssociationID=Company.AssociationI'.

Maybe the problem is really how I will put the parenthesis for the 4th join. I have followed your solution though. It pops out the same result as above.

I have searched some codes and tutorials and this is what I have as of now.

Imports System.Data.OleDb

Public Class Search

Dim con As New OleDbConnection



Private Sub Search_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'TODO: This line of code loads data into the 'DatabaseDataSet.Association' table. You can move, or remove it, as needed.
Me.AssociationTableAdapter.Fill(Me.DatabaseDataSet.Association)
'TODO: This line of code loads data into the 'DatabaseDataSet.Sector' table. You can move, or remove it, as needed.
Me.SectorTableAdapter.Fill(Me.DatabaseDataSet.Sector)


cmboxExportOpt.Text = "Export to PDF"


' Filling the tree view
Dim SectorID As String
Dim SectorName As String
Dim SectorCount As Integer


For SectorCount = 0 To DatabaseDataSet.Sector.Count - 1
SectorID = DatabaseDataSet.Sector.Rows(SectorCount).Item(0)
SectorName = DatabaseDataSet.Sector.Rows(SectorCount).Item(1)
tvDataTable.Nodes(0).Nodes.Add(SectorID, SectorName)


Next


tvDataTable.ExpandAll()


End Sub


Private Sub btnBack_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBack.Click
Me.Close()
Homepage.Show()
End Sub

Private Sub tvDataTable_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles tvDataTable.AfterSelect
If tvDataTable.SelectedNode Is Nothing Then
dgvAssocView.DataSource = Nothing
Exit Sub
End If
If tvDataTable.SelectedNode.Name = "Sector" Then
Exit Sub
End If

Dim ID As String
ID = tvDataTable.SelectedNode.Name
dgvAssocView.DataSource = DatabaseDataSet.Association.Select("SectorID=" & ID)
End Sub

Private Sub SectorBindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
Me.Validate()
Me.SectorBindingSource.EndEdit()
Me.TableAdapterManager.UpdateAll(Me.DatabaseDataSet)

End Sub
End Class

I can only show 1 data table(Which is Sector) in the tree view and I cannot add some grandchild to the child(Association) nodes of the parent node.
Also I am getting errors like this:

Syntax error in Lookup expression: Expecting keyword 'Parent' followed by a single column argument with possible relation qualifier: Parent[(<relation_name>)].<column_name>.

Actually, I am stuck at all. I do not know how to start. I can't even connect the treeview to my database's datatable. So any enlightenment into this matter is highly appreciated.

Yes, I do want my datatable to be displayed

The actual treeview hierarchy that I will be doing is like this, Sector>Association>Company>Location>Product>Raw Materials. So 1 Parent will be having multiple sub-parents and child.