VB.NET->组合框随机索引

Question

I have a question regarding comboboxes in VB.net 2010.

In my database I have 4 fields: eg:

idDetails | DetailsShortCode | Details_Explain | DetailsSortOrder
{autonum}1| DOA              | Death on Arrival| 5
{autonum}2| NDI              | No Display      | 10
{autonum}3| QQA              | In Research     | 4

etc..

These values I pull out of the dbase (mySQL) and insert into a CheckedListBox . I display the values as DetailsShortCode & " - " & Details_explain. I use a [for loop] to create index numbers, because the sort order is based on the Details Sort order. Which means that VB.net gets 'fed' with the results in the following order:

idDetails | DetailsShortCode | Details_Explain | DetailsSortOrder
3         | QQA              | " ... "         | 4
1         | DOA              | "...."          | 5
2         | NDI              | " ... "         | 10

If i put this in the listbox, the error I shall receive is '3 is an incorrect value for 'index'" Due to the fact that VB.net expects that the CheckedListBox (and also ComboBox ) index always is in a sequential order, as in 0,1,2,3,4..etc..

The problem is the fact that orders in the database can change, items can change, and I have a field in another table containing a comma separated list of the details selected (eg 1;10;14;12;) This means that 1 always must be the item with PrimaryKey 1, and that the displayed item on that index must always be the same...

so what I need, is to know how I can use the Primary Key as an Index Number, and let VB.Net not throw an error when the Index is in a random order.., or give the items a hidden value (like in HTML and PHP), in which I can just use the [for loop] indexes..

---

This is the code I use to insert items to the Details CheckedListBox

Function LoadComboBoxes(ByVal CB As String)
    Dim SQLtext = ""
    Select Case CB
        Case "Details"
            SQLtext = "Select " & _
                      "idDetails, " & _
                      "DetailsCode, " & _
                      "DetailsExplain, " & _
                      "DetailsSortOrder " & _
                      "FROM Details order by DetailsSortOrder"
Dim i = -1
    Dim dr As MySqlDataReader

    Dim cmd As New MySqlCommand(SQLtext, dbconn)
    connect()
    dr = cmd.ExecuteReader(CommandBehavior.CloseConnection)

    CLBDetails.Items.Clear()
    While dr.Read
       i += 1
       CLBDetails.Items.Insert(i, .GetString(1) & " - " & dr.GetString(2))
     End While

end select
end function

Answer 1

The easiest way might be to use a DataGridView which should have all the functionality of the CheckedComboBox plus the ability to keep the data intact as column data and allow you to reference the ID column as an ID Column rather than an ID aliased as an Index.

Depending on what a CheckedComboBox is (there are lots of these around) and what it inherits from, you should be able to store objects there:

Class DisplayItem
     Friend ID as Long

     DetailsShortCode As String

     Details_Explain As String
     DetailsSortOrder As String

   Public Function overrides ToString As String
       ' depending on the CheckedComboBox add column seperators?
       return DetailsShortCode & Details_Explain & DetailsSortOrder 
   End Function
End Class

Adding an object such as this to the control lets you retain the PK ref:

   ccb.Items(N).ID

While the ToString function lets you format the output as desired. Further, you could create a List(Of DisplayItem) or BindingList(Of DisplayItem) and drive the CheckedComboBox by binding the datasource to the List. A DGV is still easier...