mysql - .NET - Importing class with connection to database -

i want import class class don't have write same code x times.

i have file connection database called connectdb.vb.

imports mysql.data.mysqlclient  namespace connectdb1     public class connectdb         dim connection new mysqlconnection("server=localhost; userid=root;                                  password=root; database=something")          public sub doconnection()             try                 connection.open()             catch ex exception                 msgbox("error")             end try         end sub     end class end namespace 

and want import connectdb.vb file1.vb

imports mysql.data.mysqlclient imports myapp.connectdb1  public class file1      dim connectdatabase new connectdb     dim connection new mysqlconnection("server=localhost; userid=root; password=root; database=something")      private sub file1_load(byval sender system.object, byval e system.eventargs) handles mybase.load         'doconnection()         connectdatabase.doconnexion()     end sub      'private sub doconnection()     '    try     '        connection.open()     '    catch ex exception     '        msgbox("error")     '    end try     'end sub      private sub addproduct()         dim dbcomm mysqlcommand         dim dbread mysqldatareader          if txtboxquantity.text <> "" , txtboxprice.text <> "" , txtboxproduct.text <> ""             dbcomm = new mysqlcommand("insert 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 system.object, byval e system.eventargs) handles agregarproducto.click         addproduct()     end sub end class 

but when run code it's suposed save data in db gives me error:

invalidoperationexception unhandled. connection must valid , open.

connectdb.vb connects database since debugged , connects db, when want sql sentence in file1.vb gives error.

without trying import class code works, i'm trying improve code, can see commented code code used connect database.

try adding this

public sub new()   connectdatabase = new connectdb()   connection = new mysqlconnection("server=localhost; userid=root; password=root; database=something") end sub