Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
 
        Dim Verindungsserver As String = "localhost"
        Dim Benutzername As String = "root"
        Dim Passwort As String = "abcd"
        Dim Datenbank1 As String = "telegrammserver"
 
        conn = New MySqlConnection()
        conn.ConnectionString = "server=" & CStr(Verindungsserver) & ";" _
        & "user id=" & CStr(Benutzername) & ";" _
        & "password=" & CStr(Passwort) & ";" _
        & "database=" & CStr(Datenbank1) & ""
 
        conn.Open()
    End Sub
 
    Private Sub btDBCon_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles btDBCon.Click
 
        Dim myCommand As New MySqlCommand
        Dim myAdapter As New MySqlDataAdapter
        Dim myData As New DataTable
        Dim SQL As String
 
        SQL = "SELECT * FROM Mustertab"
 
        myCommand.Connection = conn
        myCommand.CommandText = SQL
 
        myAdapter.SelectCommand = myCommand
        myAdapter.Fill(myData)
 
        DataGridView1.DataSource = myData
 
        DataGridView1.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.AllCells
 
    End Sub

error BC30002: Type 'MySqlConnection' is not defined.
error BC30002: Type 'MySqlCommand' is not defined.
error BC30002: Type 'MySqlDataAdapter' is not defined.