insert and update database table rows using textboxes

[kumsay]

Hi there, I'm having a problem with updating and/or inserting rows in a table in my database. I have a form with a combobox, 10 textboxes, and save button. Here, the combobox if filled with illnesses from the diagnose table in my database. Diagnose table's structure is: f_id, illness, symptoms, so an illness can have many symptoms. If an item is selected from the combobox, the symptoms will be displayed on the textboxes. I already got this working. My problem is that I should make it able to insert or update the rows in the table. Here's my code for reading the illness and symptoms:

Call Connect()
            Dim str As String
            str = "Select sname from diagnose where first_aid = @ill"
            cmd.Parameters.AddWithValue("ill", cmbRecord.Text)
            cmd.Connection = myConn
            cmd.CommandText = str
            dtr = cmd.ExecuteReader

            Dim symptoms As New List(Of String)
            While dtr.Read()
                symptoms.Add(dtr("sname"))
            End While
            'set available symptoms
            Dim arrayOfTextboxes() As TextBox = {symp0, symp1, symp2, symp3, symp4, symp5, symp6, symp7, symp8, symp9}
            Dim i As Integer = 0
            For i = 0 To symptoms.Count - 1
                arrayOfTextboxes(i).Text = symptoms(i)
            Next
            'clear other textboxes
            For j = i To UBound(arrayOfTextboxes)
                arrayOfTextboxes(j).Text = String.Empty
            Next
            myConn.Close()

and here's my code for inserting or updating. I get error "Parameter 'ill' has already been defined."

Call Connect()
            If Duplicate() = False Then
                Dim dt As New DataTable("diagnose")
                Dim row As DataRow
                Dim arrayOfTextboxes() As TextBox = {symp0, symp1, symp2, symp3, symp4, symp5, symp6, symp7, symp8, symp9}
                Dim symptoms As New List(Of String)
                STRSQL = "insert into diagnose values (@ill, @sym)"
                Using myCmd = New MySqlCommand(STRSQL, myConn)
                    myConn.Open()

                    Dim i As Integer = 0
                    For i = 0 To arrayOfTextboxes.Count - 1
                        If String.IsNullOrEmpty(arrayOfTextboxes(i).Text) Then Continue For
                        If arrayOfTextboxes(i).Text <> "" Then
                            myCmd.Parameters.AddWithValue("ill", cmbRecord.Text)
                            myCmd.Parameters.AddWithValue("sym", arrayOfTextboxes(i).Text)
                            row = dt.NewRow()
                            myCmd.ExecuteNonQuery()
                        End If
                    Next
                    MsgBox("Record Added")
                    myConn.Close()
                End Using

                'Else
                '    STRSQL = "Update diagnose set first_aid = @ill, sname = @symp where first_aid = @ill"
                '    Using myCmd = New MySqlCommand(STRSQL, myConn)
                '        myConn.Open()
                '        myCmd.Parameters.AddWithValue("ill", cmbRecord.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp0.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp1.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp2.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp3.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp4.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp5.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp6.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp7.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp8.Text)
                '        myCmd.Parameters.AddWithValue("sym", symp9.Text)
                '        myCmd.ExecuteNonQuery()
                '    End Using
                '    MsgBox("Record Updated")
                '    myConn.Close()
            End If

The codes marked as comment is my code for updating, but that's not working so I set it aside for the mean time. The table looks like this:
f_id| illness | symptom
1 | fever | fever
2 | fever | hot temperature
3 | fever | dizziness
4 | fever | headache
so in that case, say I chose fever in the combobox then it will display the symptoms on the 4 textboxes. If the user made changes, the Duplicate() function checks if the combobox value already have a record. If true then it will update. Say the user added another symptom, so if save button is clicked, fever will add another row with the added symptom. If false, then a new record will be added, which means new row or rows will be added in the table dependeng on the number of symptoms inputted on the textboxes. So, say 'cold' is to be added as a new record and I entered 2 symptoms, this means that I used 2 of the 10 textboxes in the form, then 2 rows will be added on the table. I already spent a day trying to make this work but failed. Please help me make this work. Any help will be greatly appreciated. Thanks in advance, Godbless

[kumsay]

ok I'm getting closer..I can add a row in the database now but only 1. Say I entered cold as new illness then filled the 2 textboxes with symptoms, it only stores the symptom on the first textbox. So it only add 1 row with 1 symptom on the table. Also, I still get the "Parameter 'ill' has already been defined". Anybody have an idea?

[Mikkeee]

Kumsay, it looks like you keep adding to your parameter collection. You need to either add the parameters to your command before your loop and just update the values OR you need to clear them before you use AddWithValue.