vb.net - Error when inserting data into a MS Access table -

how can insert data ms access table? when try, getting error.

code:

if textbox1.text = nothing , textbox2.text = nothing     msgbox("no username , password inserted")     textbox1.focus()  else      if not con.state = connectionstate.open         'open connection if not yet open     end if      cmd.connection = con     'add data table     cmd.commandtext = "insert logintable(username, password, typeofuser) values ('" & me.textbox1.text & "', '" & me.textbox2.text & "', '" & me.combobox1.text & "')"      cmd.executenonquery()      'refresh data in list      'close connection     con.close() end if 

first, don't open connection:

con.open() 

next, password reserved word in ms access. need wrap password in square brackets:

[password] 

you concatenating strings instead of using paramaters:

cmd.parameters.add("@username", oledbtype.varchar).value = txtusername.text cmd.parameters.add("@password", oledbtype.varchar).value = txtpassword.text cmd.parameters.add("@typeofuser", oledbtype.varchar).value = cmbtypeofuser.text 

look @ giving textbox , combobox controls proper name instead of using textbox1, textbox2 , combobox1. helps identify correctly each control:

txtusername txtpassword cmbtypeofuser 

move away using msgbox , use messagebox.show. msgbox exists vb6 , ends delegating messagebox anyway makes sense use messagebox.show:

messagebox.show("no username , password inserted") 

lastly consider implementing using close , dispose of sql objects:

using cmd new oledbcommand(command, connection)  end using 

all code this:

if txtusername.text = nothing , txtpassword.text = nothing      messagebox.show("no username , password inserted")     textbox1.focus()  else      using con new oledbconnection(connectionstring),           cmd new oledbcommand("insert [logintable] ([username], [password], [typeofuser]) values (@username, @password, @typeofuser)", con)          con.open()          cmd.parameters.add("@username", oledbtype.varchar).value = txtusername.text         cmd.parameters.add("@password", oledbtype.varchar).value = txtpassword.text         cmd.parameters.add("@typeofuser", oledbtype.varchar).value = cmbtypeofuser.text          cmd.executenonquery()      end using  end if 

^{it's outside scope of question @ encrypting passwords. storing them plain text bad practice. have @ question; best way store password in database, may give ideas on how best this.}