Treview - Inseire valori e leggere valori

' inserisce i valori


Dim root, node1, node2 As TreeNode

' Root node has a value but no ID.

root = Me.TreeView1.Nodes.Add("Root")

' node1 and node2 contain values and IDs

' ID is stored in Tag property, enabling lookup by ID

node1 = root.Nodes.Add("Value1")
node1.Tag = "1"

node2 = root.Nodes.Add("Value2")
node2.Tag = "2"

root.Expand()



Leggere dopo il click

Private Sub TreeView1_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterSelect

Dim selectedID As String

'**try casting or converting Tag object to a string

'if the conversion succeeds selectedID will have a valid value;

'else TryCast will return Nothing

selectedID = TryCast(e.Node.Tag, String)

'**test if selectedID is null using IsNot operator

If selectedID IsNot Nothing Then
Me.SelectedIDTextbox.Text = selectedID
Else
Me.SelectedIDTextbox.Text = "[Nothing]"
End If

Me.SelectedValueTextbox.Text = e.Node.Text
End Sub