AddHandler SelectedIndexChanged Problem

[qasd3]

Hi,
I just have a problem that I can not workout a solution to.

I have a gridview which gets a bunch of controls created dynamically. What I want to be able to do is have one dropdownlist selection determine what is in the other dropdownlist control. I have the first one being populated fine but just have a problem getting the first selected index value to the second dropdownlist.

For the dropdownlist I have the following:

AddHandler field_ddl.SelectedIndexChanged, AddressOf OnSelectedIndexChanged

Which calls

    Private Sub OnSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
 
        Dim myDropDownListName As String
        Dim myNewValue As String
 
        myNewValue = DirectCast(sender, DropDownList).SelectedValue
        myDropDownListName = DirectCast(sender, DropDownList).ID
 
        myDropDownListName = StringFunctions.JustColumnName(myDropDownListName)
 
        'ParameterArray.Add(myDropDownListName)
 
 
        Dim myHTTP As String
        HttpContext.Current.Session(myDropDownListName) = myNewValue
 
        myHTTP = HttpContext.Current.Session(myDropDownListName)
 
 
    End Sub

What happens is that yes the session variable does get populated at some stage but seems to be happening too late. I want to use the value to build the SQL that will fill the second dropdownlist but the value is not got until after the postback and controls have been populated.

Is there a way to make sure that the OnSelectedIndexChanged sub be called before the postback?

Thanks

[kenobewan]

Welcome to TSDN. Have you tried not ispostback?

[qasd3]

Sorry I dont think that I understand what you are sujesting. The code that I have supplyed is in a seprate class that is being called from the page. What is happening is that the dropdownlist does do the postback there are things that run in the page_load that recreate the items in the gridview. The dropdownlist maintains the selected value from the user. The sub for the dropdownlist item being changed does get fired but this happens after the page_load has recreated the dropdownlists so the value that the user selected can not be used before the dropdownlist items are populated. So what I need is the value from the dropdownlist that has changed to be avaliable before the dropdownlists are being recreated. So something like before the postback or just after the postback in the page_load section is where I think that I need to get the value.

Hope that this gives a bit more information about the problem. Thanks for your reply.

[kenobewan]

My bad - I misread your question. My belief is that you don't need things to happen before page load or postback. It is the order of things that is important. If you cant create the session earlier in the event you could try using threads to ensure it is created. Here is an article that may help:
Threading in ASP.NET

[mschnell]

You could try the following

Session("sessionName") = DataBaseTable.Attribute
DropDownList.DataBind()

for example.

The dataBind will make the session variable apply to the drop down list when you call it.