Imports System.IO


Public Class Form1

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

        cargarCarpetas("C:/Manuales")
    End Sub
    Public Sub cargarSubcarpetas(ByVal rutaRaiz As String,
              ByVal nodoTree As Windows.Forms.TreeNode)
        On Error Resume Next
        Dim carpetaActual As String
        Dim indice As Integer

        If nodoTree.Nodes.Count = 0 Then
            For Each carpetaActual In
                    My.Computer.FileSystem.GetDirectories(rutaRaiz)
                indice = carpetaActual.LastIndexOf(System.IO.Path.PathSeparator)
                nodoTree.Nodes.Add(carpetaActual.Substring(indice + 1,
                     carpetaActual.Length - indice - 1))
                nodoTree.LastNode.Tag = carpetaActual
                nodoTree.LastNode.ImageIndex = 0
            Next
        End If
    End Sub

    Public Sub cargarCarpetas(ByVal rutaRaiz As String)
        Dim nodoBase As System.Windows.Forms.TreeNode

        If IO.Directory.Exists(rutaRaiz) Then
            If rutaRaiz.Length <= 3 Then
                nodoBase = TreeView1.Nodes.Add(rutaRaiz)
            Else
                nodoBase = TreeView1.Nodes.Add(
                    My.Computer.FileSystem.GetName(rutaRaiz))
            End If
            nodoBase.Tag = rutaRaiz
            cargarSubcarpetas(rutaRaiz, nodoBase)
        Else
            Throw New System.IO.DirectoryNotFoundException()
        End If
    End Sub

    Private Sub TreeView1_AfterExpand(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterExpand
        Dim n As System.Windows.Forms.TreeNode
        For Each n In e.Node.Nodes
            cargarSubcarpetas(n.Tag, n)
        Next
    End Sub

    Private Sub TreeView1_MouseDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseDoubleClick

        Dim ruta As String
        ruta = TreeView1.SelectedNode.ToString.Substring(9)
        TextBox1.Text = ruta
        Shell("explorer.exe root=" & TextBox1.Text & " ", vbNormalFocus)

    End Sub
End Class

ArUsu = reader.GetString(2).ToUpper

 Dim sql As String = "SELECT name_comp, tipo_user FROM table_users where nom_user = @username and pass_user = @password "

CREATE TABLE `table_users` (
	`id_user`	INTEGER,
	`nom_user`	TEXT DEFAULT 25,
	`pass_user`	TEXT,
	`name_comp`	TEXT DEFAULT 50,
	`tipo_user`	TEXT DEFAULT 25,
	PRIMARY KEY(id_user)
);

Imports System.Data.SQLite
Public Class Form2

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            Dim NmUser, TpUser, ArUsu As String
            Dim reader As SQLiteDataReader
            Dim conexSQLite As New SQLiteConnection("data source=C:\Users\Admin\Downloads\SQLiteDatabaseBrowserPortable\Data\libreria_db")
            Dim sql As String = "SELECT name_comp, tipo_user FROM table_users where nom_user = @username and pass_user = @password "
            Dim cmd As New SQLiteCommand(sql, conexSQLite)

            conexSQLite.Open()

            cmd.Parameters.Add("@username", SqlDbType.VarChar, 20).Value = TextBox1.Text
            cmd.Parameters.Add("@password", SqlDbType.VarChar, 20).Value = TextBox2.Text

            reader = cmd.ExecuteReader()

            If reader.Read Then
                NmUser = reader.GetString(0).ToUpper
                TpUser = reader.GetString(1).ToUpper
                ArUsu = reader.GetString(2).ToUpper

                If NmUser = "ADMINISTRADOR" Then

                    Form1.Show()

                End If

                MessageBox.Show("Bienvenido " & NmUser & " al sistema.")

            Else
                MsgBox("Usuario o password incorrecto, trate otra vez..")

            End If

            reader.Close()
            conexSQLite.Close()


        Catch ex As Exception
            MsgBox("ERROR." & ex.Message)

        End Try



    End Sub
End Class

OpenPDF.ShowDialog()
        PDFcontenedor.src = OpenPDF.FileName