RadioButtonList created in the page load event

[William LaMartin]

If I create a RadioButtonList with, say, two items, then after the page
loads and I select one of the items and then click on a button whose click
event contains some code to display the RadioButtonlLis t's selected value,
there is nothing.

On a postback, with the dynamically created button list visible on the page
and the first item selected, if I try some code like "If
Me.RadioButtonL ist1.Items(0).S elected = True Then.......", then I get an
index out of range error. It is like the RadiobuttonList does not really
exits.

For RadioButtonList s that are simply dropped on a page with their values set
in the properties window in Visual Studio, there is no problem.

So, how does one determine whether a dynamically created RadioButtonList
item is selected and if so what its selected value is?

[Teemu Keiski]

Hi,

if you create the RadioButtonList at Page_load, it's state/data is available
after postback events which happen after Page_Load have occurred.

i.e page lifecycle on every request is:

1. Instantiate
2. Initialize
3. TrackViewState
4. LoadViewState (postback)
5. Load postback data (postback, IPostBackDataha ndler.LoadPostd ata)
6. Load
7. Load postback data for dynamical controls added on Page_Load (postback)
8. Raise Changed Events (postback,
IPostBackDataha ndler.RaisePost DataChanged)
9. Raise postback event (postback, IPostBackEventH andler.RaisePos tBackEvent)
10.PreRender
11. SaveViewState
12. Render
13. Unload
14. Dispose

As you can see, so if on initial request you create the RadioButtonList in
Page_load, it hasn't yet loaded its state at Page_Load phase on postback. As
a solution, you could move the creation of control into Page_Init, when
state is available at Page_Load, or move checking the selection to PreRender
phase.

--
Teemu Keiski
MCP, Microsoft MVP (ASP.NET), AspInsiders member
ASP.NET Forum Moderator, AspAlliance Columnist
"William LaMartin" <la******@tampa bay.rr.com> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. ..

If I create a RadioButtonList with, say, two items, then after the page
loads and I select one of the items and then click on a button whose click
event contains some code to display the RadioButtonlLis t's selected value,
there is nothing.

On a postback, with the dynamically created button list visible on the page and the first item selected, if I try some code like "If
Me.RadioButtonL ist1.Items(0).S elected = True Then.......", then I get an
index out of range error. It is like the RadiobuttonList does not really
exits.

For RadioButtonList s that are simply dropped on a page with their values set in the properties window in Visual Studio, there is no problem.

So, how does one determine whether a dynamically created RadioButtonList
item is selected and if so what its selected value is?

[William LaMartin]

Thanks for the suggestions. I put the code that creates the RadioButtonList
in Page_Init with no change. I then put the check for selected value in
Page_PreRender, also with no change. The code used is below.

I will study your sequence of events and see if that can somehow lead to a
solution to the problem. I have run into similar situations when I wanted
to set a Session variable and then use it on a button click, but the session
variable was a click behind when I needed it.

Code that creates the RadioButtonList :

Dim filepath As String
Dim filename As String
Dim RadioButtonList 1 As New RadioButtonList
RadioButtonList 1.ID = "AcrobatRBL "
RadioButtonList 1.Visible = True
RadioButtonList 1.EnableViewSta te = True
RadioButtonList 1.AutoPostBack = True
Me.Panel1.Visib le = True
Me.Panel1.Contr ols.Clear()
filepath = Server.MapPath( ".") & "\acrobat_files \"
Dim CurrentDirector y As New System.IO.Direc toryInfo(filepa th)
Dim FileArray() As System.IO.FileI nfo
FileArray = CurrentDirector y.GetFiles()
Dim i As Integer
For i = FileArray.GetLo werBound(0) To FileArray.GetUp perBound(0)
Dim mylistItem As New ListItem
mylistItem.Text = FileArray(i).Na me
mylistItem.Valu e = FileArray(i).Na me
RadioButtonList 1.Items.Add(myl istItem)
Next i
Me.Panel1.Contr ols.Add(RadioBu ttonList1)

Code to check the selected value:

Me.Label2.Text = Me.RadioButtonL ist2.SelectedVa lue
"Teemu Keiski" <jo****@aspalli ance.com> wrote in message
news:e1******** *****@tk2msftng p13.phx.gbl...

Hi,

if you create the RadioButtonList at Page_load, it's state/data is available after postback events which happen after Page_Load have occurred.

i.e page lifecycle on every request is:

1. Instantiate
2. Initialize
3. TrackViewState
4. LoadViewState (postback)
5. Load postback data (postback, IPostBackDataha ndler.LoadPostd ata)
6. Load
7. Load postback data for dynamical controls added on Page_Load (postback)
8. Raise Changed Events (postback,
IPostBackDataha ndler.RaisePost DataChanged)
9. Raise postback event (postback, IPostBackEventH andler.RaisePos tBackEvent) 10.PreRender
11. SaveViewState
12. Render
13. Unload
14. Dispose

As you can see, so if on initial request you create the RadioButtonList in
Page_load, it hasn't yet loaded its state at Page_Load phase on postback. As a solution, you could move the creation of control into Page_Init, when
state is available at Page_Load, or move checking the selection in Page_PreRend phase.

--
Teemu Keiski
MCP, Microsoft MVP (ASP.NET), AspInsiders member
ASP.NET Forum Moderator, AspAlliance Columnist
"William LaMartin" <la******@tampa bay.rr.com> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. ..

If I create a RadioButtonList with, say, two items, then after the page
loads and I select one of the items and then click on a button whose click event contains some code to display the RadioButtonlLis t's selected value, there is nothing.

On a postback, with the dynamically created button list visible on the

page

and the first item selected, if I try some code like "If
Me.RadioButtonL ist1.Items(0).S elected = True Then.......", then I get an
index out of range error. It is like the RadiobuttonList does not really exits.

For RadioButtonList s that are simply dropped on a page with their values

set

in the properties window in Visual Studio, there is no problem.

So, how does one determine whether a dynamically created RadioButtonList
item is selected and if so what its selected value is?

[William LaMartin]

Problem solved. It really had nothing to do with the RadioButtonList being
created on the fly. The problem was caused by there being to declarations
of the RadioButtonList--one at the page level and one at the page_load event
level. When I realized this and removed the one at the page_load event
level, there ceased to be a problem.
"William LaMartin" <la******@tampa bay.rr.com> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. ..

If I create a RadioButtonList with, say, two items, then after the page
loads and I select one of the items and then click on a button whose click
event contains some code to display the RadioButtonlLis t's selected value,
there is nothing.

On a postback, with the dynamically created button list visible on the page and the first item selected, if I try some code like "If
Me.RadioButtonL ist1.Items(0).S elected = True Then.......", then I get an
index out of range error. It is like the RadiobuttonList does not really
exits.

For RadioButtonList s that are simply dropped on a page with their values set in the properties window in Visual Studio, there is no problem.

So, how does one determine whether a dynamically created RadioButtonList
item is selected and if so what its selected value is?