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Loop through Controls in dynamic table inside place holder

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Last Modified: 2013-11-26
I am using vb.net. I have a place holder in a page that is populated by a dynamic table that is added to the place holder after the user selects a value from a drop down box. Inside this dynamic table are check boxes.

The goal is to cycle through these check boxes and figure out which ones are checked after a button is pushed. The problem seems to be when the html is rendered. I tried putting code in the init event. I have attached the code.
PH_Tables is the name of the place holder control. Inside that is a dynamic table that contains the check boxes. I included the function that returns the control causing the postback - for completeness.
Public Shared Function GetPostBackControl(ByVal page As Page) As Control
        Dim control As Control = Nothing
 
        Dim ctrlname As String = page.Request.Params.Get("__EVENTTARGET")
        If ctrlname <> Nothing And ctrlname <> String.Empty Then
            control = page.FindControl(ctrlname)
        Else
            Dim ctl As String
            For Each ctl In page.Request.Form
                Dim c As Control = page.FindControl(ctl)
                If TypeOf c Is System.Web.UI.WebControls.Button Then
                    control = c
                    Exit For
                End If
            Next
        End If
        Return control
    End Function
    Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
        Dim s As Control
        Dim cntrl As Control
        Dim cb_cntrl As CheckBox
        Dim SB_ext_desc As New StringBuilder
        Dim testme As String
 
        s = GetPostBackControl(Me)
 
        If (Not (IsNothing(s)) AndAlso s.ID = "Button1") Then
 
            For Each cntrl In PH_tables.Controls
                testme = cntrl.ID
                If TypeOf cntrl Is CheckBox Then
                    cb_cntrl = cntrl
                    If cb_cntrl.Checked = True Then
                        SB_ext_desc.Append(cntrl.ID)
                        SB_ext_desc.Append(" ")
                    End If
                End If
 
            Next
            Session("s_ext_desc") = SB_ext_desc
            Session("do_update") = True
        End If
 
    End Sub

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You  mention when, but not exactly _what_ the problem is.

I can guess that the dynamic control/table/etc. does not exist on postback. It has to be re-created or the control no longer exists on postback.

Author

Commented:
Oops
I can not get to the check boxes. I have tried looping through the tabel and place holder controls in page init and pre render. The check boxes don't show up.
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Author

Commented:
I will try that tomorrow.

Author

Commented:
Worked great. Thanks! The checkbox was in the TableCell.
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