.NET 4.x Загрузка данных из БД в переменные - Visual Basic .NET

Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
       Dim a1 As String
       Dim a2 As String
       Dim a3 As Date
       Dim a4 As String
        a1 = ComboBox1.Text
        Dim Connect1 As New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & Path)
        zSQL1 = "SELECT p1, p2, p3, p4 FROM Printer WHERE p1=a1 "
        Dim Command1 As New OleDb.OleDbCommand(zSQL1, Connect1)
        Connect1.Open()
        Command1.ExecuteNonQuery()
        Connect1.Close()
        a2=?
        a2=?
        a4=?
    End Sub