AddHandler problem

[Shawn]

Hi.
I'm trying to add an event to a DropDownList from my code, but so far I
haven't been able to do it right. The DropDownList is inside a DataGrid. The
reason why I'm not adding an onSelectedIndexChanged attribute in the html
code is because not all of the DropDownLists in the DataGrid is to have this
event. Here is a simplified version of my code:

For i = 0 To dgParameter.Items.Count - 1
dataGridItem = dgParameter.Items(i)

myDDL = CType(dataGridItem.FindControl("ddlValue"), DropDownList)
myDDL.AutoPostBack = True
AddHandler myDDL.SelectedIndexChanged, AddressOf
myDDL_SelectedIndexChanged
Next

Public Sub myDDL_SelectedIndexChanged(ByVal sender As Object, ByVal e As
System.EventArgs)
'...
'...
End Sub

I tried replacing the AddHandler line with this one, but still nothing.
myDDL.Attributes.Add("onselectedindexchanged", "myDDL_SelectedIndexChanged")

Any help appreciated!

Thanks,
Shawn

 

[Kevin Spencer]

Hi Shawn,

Most probably your issue is one of sequence. Events in a Page and other
System.Web.UI.Controls fire in a certain sequence. The following article
lists the sequence of events:

http://msdn.microsoft.com/library/d...guide/html/cpconControlExecutionLifecycle.asp

--
HTH,
Kevin Spencer
..Net Developer
Microsoft MVP
Big things are made up
of lots of little things.

 

[Shawn]

Hi Kevin,

Thanks for answering. Unfortunately I didn't understand enough of it to come
up with a solution

Do you think you could help me along a little bit? Maybe give me an example
I could try out?



Thanks,

Shawn

 

[Guest]

Can you please clarify this portion of your code

<quote
myDDL = CType(dataGridItem.FindControl("ddlValue"), DropDownList
</quote

That is, how are you finding the "ddlValue" for the exact control. Once it is in a templated item, .NET will create the *true* UniqueID for it and it will not simply be the name you gave it. (something like "dgParameter:_ct14ropDownName") Which means your FindControl function will likely not work

To add functionality to specific records in your datagrid - perhaps you should make a routine that occurs on the DataGrid.ItemCreated event that adds that dropdown for you

Here is a sample

Private Sub dgTest_ItemCreated(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles dgTest.ItemCreate
Dim ddlTest As New DropDownLis
ddlTest.AutoPostBack = Tru
AddHandler ddlTest.SelectedIndexChanged, AddressOf SpecialDropDownHandle
e.Item.Cells(0).Controls.Add(ddlTest
End Sub