no mostrar icono windows form

Propiedades
ShowIcon = False


fuente

windows form activo

 If Application.OpenForms.OfType(Of windows_form1).Any Then
            MessageBox.Show("windows form1")
        ElseIf Application.OpenForms.OfType(Of windows_form2).Any Then
            MessageBox.Show("windows_form2")
        End If

fuente

Deshabilitar botón salir(exit) WindowsForm

Protected Overrides ReadOnly Property CreateParams() As System.Windows.Forms.CreateParams
        Get
            Dim cp As CreateParams = MyBase.CreateParams
            Const CS_NOCLOSE As Integer = &H200
            cp.ClassStyle = cp.ClassStyle Or CS_NOCLOSE
            Return cp
        End Get
End Property

Esconder WindowsForm

Propiedades
Opacity: 0%
ShowIcon: False
ShowInTaskbar: False
Text: ""

fuente: https://www.youtube.com/watch?v=qWfebmTDmCE

Volver al icono por defecto en WindowsForm

Properties
Icon
click botón derecho mouse
seleccionar Reset

TreeView para opciones

Public Class Form1


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

        Dim node As TreeNode = TreeView1.SelectedNode

        Select Case node.Text

            Case "General"
                'general.TextBox1.Enabled = False
                f.Dispose()
                f = New general()
                f.TopLevel = False
                Me.Panel1.Controls.Add(f)
                f.Dock = DockStyle.Fill
                f.Show()



            Case "Factura electrónica"
                f.Dispose()
                f = New fa()
                f.TopLevel = False
                Me.Panel1.Controls.Add(f)
                f.Dock = DockStyle.Fill
                f.Show()
            Case "Nota de credito"
                f.Dispose()
                f = New nc()
                f.TopLevel = False
                Me.Panel1.Controls.Add(f)
                f.Dock = DockStyle.Fill
                f.Show()


        End Select

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load



        'TreeView1.HideSelection = True
        TreeView1.TabIndex = 0

        f = New general()
        f.TopLevel = False
        Me.Panel1.Controls.Add(f)
        f.Dock = DockStyle.Fill
        f.Show()
    End Sub
End Class