.NET - Importing class with connection to database - mysql

Question

I want to import a class to another class so that I don't have to write the same code X times.
I have a file with the connection to the database called connectDB.vb.
Imports MySql.Data.MySqlClient
Namespace connectDB1
Public Class connectDB
Dim connection As New MySqlConnection("Server=localhost; UserId=root;
Password=root; Database=something")
Public Sub doConnection()
Try
connection.Open()
Catch ex As Exception
MsgBox("Error")
End Try
End Sub
End Class
End Namespace
And I want to import connectDB.vb to File1.vb
Imports MySql.Data.MySqlClient
Imports MyApp.connectDB1
Public Class File1
Dim connectDataBase As New connectDB
Dim connection As New MySqlConnection("Server=localhost; UserId=root; Password=root; Database=something")
Private Sub File1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'doConnection()
connectDataBase.doConnexion()
End Sub
'Private Sub doConnection()
' Try
' connection.Open()
' Catch ex As Exception
' MsgBox("Error")
' End Try
'End Sub
Private Sub addProduct()
Dim dbcomm As MySqlCommand
Dim dbread As MySqlDataReader
If txtBoxQuantity.Text <> "" And txtBoxPrice.Text <> "" And txtBoxProduct.Text <> "" Then
dbcomm = New MySqlCommand("insert into products (price, stock, name) values(#price, #stock, #name)", connection)
dbcomm.Parameters.AddWithValue("#price", txtBoxPrice.Text())
dbcomm.Parameters.AddWithValue("#stock", txtBoxQuantity.Text())
dbcomm.Parameters.AddWithValue("#name", txtBoxProduct.Text())
dbread = dbcomm.ExecuteReader() ' GIVES ERROR
dbread.Close()
End If
End Sub
Private Sub add_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles agregarProducto.Click
addProduct()
End Sub
End Class
But when I run this code that it's suposed to save the data in the DB it gives me this error:
InvalidOperationException was unhandled. Connection must be valid and open.
connectDB.vb connects to the database since I debugged and it connects to the DB, but when I want to do some sql sentence in the File1.vb it gives that error.
Without trying to import the class the code works, but I'm just trying to improve my code, as you can see the commented code is the code I used to connect to the database.

Answer 1

Try adding this
Public Sub New()
connectDataBase = New connectDB()
connection = New MySqlConnection("Server=localhost; UserId=root; Password=root; Database=something")
End Sub