Question

I am trying to insert multiple rows in a listitems to a database using parameters.
But it won’t give me any errors, and also won’t insert any data in the table.
does anyone have any ideas on this one?

  strSQL = "insert into tbltrans2 (transid,itemcode,itemname,qty,price,[total],btw) values ( ?,?,?,?,?,?,?)"
    Using cn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\POS.mdb"), _
          cmd As New OleDbCommand(strSQL, cn)

        cmd.Parameters.Add("?", OleDbType.VarChar).Value = txtTransId.Text
        cmd.Parameters.Add("?", OleDbType.VarChar, 10)
        cmd.Parameters.Add("?", OleDbType.VarChar, 50)
        cmd.Parameters.Add("?", OleDbType.Integer)
        cmd.Parameters.Add("?", OleDbType.Decimal)
        cmd.Parameters.Add("?", OleDbType.Decimal)
        cmd.Parameters.Add("?", OleDbType.VarChar, 50)

        cn.Open()
        For Each ls As ListViewItem In ListItems.Items
            cmd.Parameters(1).Value = ls.Tag
            cmd.Parameters(2).Value = ls.SubItems(0).Text
            cmd.Parameters(3).Value = Integer.Parse(ls.SubItems(1).Text)
            cmd.Parameters(4).Value = Decimal.Parse(ls.SubItems(2).Text)
            cmd.Parameters(5).Value = Decimal.Parse(ls.SubItems(3).Text)
            cmd.Parameters(6).Value = ls.SubItems(5).Text
        Next ls

    End Using

Hey steve, When I try that, it gives me ‘syntax error in update statement’ erro. Here is my code:

 Try
        strSQL = "UPDATE set instock = ? where itemcode= ?"
        Using cn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\POS.mdb"), _
               cmd As New OleDbCommand(strSQL, cn)
            cn.Open()
            For Each ls As ListViewItem In ListItems.Items
                cmd.Parameters.Add("?", OleDbType.Integer).Value = 100
                cmd.Parameters.Add("?", OleDbType.VarChar).Value = ls.Tag
                cmd.ExecuteNonQuery()
            Next ls
            cn.Close()
        End Using
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try

Now, I still need help with decreasing the stock. Here is the code that I use, but it isn’t working.

  strSQL = "UPDATE tblitem set instock ='instock'- ? where itemcode = ?"
            Using cn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\POS.mdb"), _
                   cmd As New OleDbCommand(strSQL, cn)
                cn.Open()
                For Each ls As ListViewItem In SalesListItems.Items
                    If Not (ls.SubItems(1).Tag(0) = "n") Then
                        cmd.Parameters.Add("?", OleDbType.Integer).Value = ls.SubItems(1).Text
                        cmd.Parameters.Add("?", OleDbType.VarChar, 10).Value = ls.Tag
                        cmd.ExecuteNonQuery()
                    End If
                Next ls
                cn.Close()
            End Using

Answer 1

You are missing the execute part

For Each ls As ListViewItem In ListItems.Items 
   cmd.Parameters(1).Value = ls.Tag 
   cmd.Parameters(2).Value = ls.SubItems(0).Text 
   cmd.Parameters(3).Value = Integer.Parse(ls.SubItems(1).Text) 
   cmd.Parameters(4).Value = Decimal.Parse(ls.SubItems(2).Text) 
   cmd.Parameters(5).Value = Decimal.Parse(ls.SubItems(3).Text) 
   cmd.Parameters(6).Value = ls.SubItems(5).Text 
   cmd.ExecuteNonQuery()
Next ls 

Also, are you certain on the input values coming from the subitems? If there isn’t a control on their effective numeric value when you add them to the ListView, then the loop could fail with an exception when you try to convert the supposed numeric value with Parse.

EDIT: This instead for an update

strSQL = "UPDATE tblitem set instock = ? where itemcode= ?"  
Using cn As New OleDbConnection("......")   
    cmd As New OleDbCommand(strSQL, cn)  
    cmd.Parameters.Add("?", OleDbType.Integer).Value = 100
    cmd.Parameters.Add("?", OleDbType.VarChar).Value = yourItemCodeValue    
    cmd.ExecuteNonQuery()
End Using    

Keep in mind that I suppose instock is a integer data type and itemcode a varchar.