Hello.  Help!

I have a page which contains a number of drop down lists containing data 
drawn from a database.  It is to be used to automatically price a 
computer system.  The number of lists varies depending on information on 
a database and user feedback.  Each list contains parts from one category 
ie CPUs, HDDs etc.

In Page_Load I grab the information required from the database and use a 
loop to add controls three per loop - one dropdownlist, one imagebutton, 
and a literal control as a breakline.  Each button is related to a 
Oncommand subroutine.  This displays as expected.

When the user clicks on a button next to any specific category, the page 
should reload with state information on current selections maintained 
and, this is the tricky bit, must add a extra dropdown list for that 
category.  

When a button is clicked a value is added to the viewstate of the page 
relating to how many times the relevant category should display.  eg if 
the button was identified with CPUs, Viewstate("CPU")=2 might be added.

On PageLoad, when controls are being generated, the viewstate for each 
category is checked and if it = 2 or more, the appropriate number of 
dropdownlists are added. 

All this works except it is one click behind.

ie

1. 1st page load: Page shows one dropdown list per category

2. Click on say CPU button: Page reloads as before, Viewstate for CPU=2 
is added AFTER controls are added in page load.  If page is reloaded 
again, 2 x CPU lists finally appear

I have found that if I load the page controls after the button command 
subroutine has had a chance to run (used Page.IsPostBack) then it won't 
run at all.  ie the button control must be generated before its 
subroutine can run.

It seems to be a catch 22.

The only solution I can think of is to add the extra control in the 
button clicked subroutine and insertinto the control collection at the 
appropriate spot.  This is difficult and messy.

Is there a workaround for this?  This is my first asp.net page and I am 
not an experienced programmer.  I would appreciate any help.

Relevant code is below:

---------------

    Sub Page_Load
        SetControls
    End Sub
       
           
    
    Sub SetControls
        
...CUT - Get the parts data here

        dvwParts = dstParts.Tables("Parts").DefaultView

...CUT - Get the category data here

        dtrCategories = cmdSelectCategories.ExecuteReader()
    
        While dtrCategories.Read()
    
            numTimesToDisplay = ViewState(dtrCategories("fldcategory"))
            If numTimesToDisplay < 1
                NumTimesToDisplay = 1
            End If

            For x = 1 to numTimesToDisplay
                dvwParts.RowFilter = "fldCategory = '" & dtrCategories
("fldcategory") & "'"
                AddDropDownList(dvwParts, dtrCategories("fldcategory"))
            Next x
    
        End While
    
    End Sub
    
    
    Sub AddDropDownList (ByRef dvwData As DataView, strCategory As String)
    
        Dim moreImageButton As New ImageButton
        moreImageButton.CommandName = strCategory
        moreImageButton.ImageURL = "images/more.gif"

        Dim aList As New DropDownList
        aList.DataTextField = "fldTitle"
        aList.DataValueField = "fldPartID"
        aList.DataSource = dvwData
        aList.DataBind()
   
        plhPlaceHolder.Controls.Add(aList)
        plhPlaceHolder.Controls.Add(moreImageButton)
        AddHandler moreImageButton.Command, AddressOf 
Me.MoreImageButton_Command
        plhPlaceHolder.Controls.Add(New LiteralControl("<BR>"))
    
    End Sub
    
       
    
    Sub MoreImageButton_Command(s As Object, e As CommandEventArgs)

            Dim strCategoryToAdd As String
            strCategoryToAdd =  e.CommandName
    
            Dim intNumTimesDisplayed As Integer
            intNumTimesDisplayed = ViewState(strCategoryToAdd)
    
            If intNumTimesDisplayed < 1
                intNumTimesDisplayed = 2
            Else
                intNumTimesDisplayed = intNumTimesDisplayed + 1
            End If
    
            ViewState(strCategoryToAdd) = intNumTimesDisplayed
    
    End Sub