Finding Value of Dynamic Control in MasterPage/ContentPage System

[dawg1998]

I have a page that creates dynamic textboxes based on the number of
fields a user chooses to fill out.

This process worked great when the page was standalone. However, when I
move to a Content/MasterPage setup, the MasterPage Form seems to be
interfering with the ability of my code to retrieve the value in the
dynamic control.

Are there any ideas on why this is happening or how to work-around the
problem? What is the syntax to find a dynamic control within a form
established on a Master Page? The two methods I have tried so far
always gets me the "Object reference not set to an instance of an
object" error.

A quick example is below. The name of the form established in the
MasterPage is "frmForm". I must place the form tags within the
MasterPage because of the presence of a SiteMap menu control that
resides in the MasterPage.

<%@ Page Language="VB" MasterPageFile= "~/Sys_Masters/MasterPage.mast er"
title="Dynamic Control in Master Page" %>

<asp:Content ID="Content1" ContentPlaceHol derID="cphConte nt"
Runat="Server">

<script runat="server">

Sub Page_Load()

Dim txtbxTextBox As New TextBox()
txtbxTextBox.ID = "txtbxTextB ox"
phPlaceHolder.C ontrols.Add(txt bxTextBox)

End Sub

Sub btnSubmit_OnCli ck(ByVal sender As Object, ByVal e As
System.EventArg s)

Dim txtbxTextBox As New TextBox()

'// Neither of the two methods below finds the control
'txtbxTextBox =
Master.FindCont rol("frmForm"). FindControl("ph PlaceHolder").F indControl("txt bxTextBox")
'txtbxTextBox = CType(Master.Fi ndControl("frmF orm").FindContr ol
"phPlaceHolder" ).FindControl(" txtbxExample"), TextBox)

lblValue.Text = txtbxTextBox.Te xt
End Sub
</script>

<asp:Label ID="lblTitle" runat="server" Text="Dynamic Control in Master
Page Test: "/>
<p />
<asp:PlaceHolde r ID="phPlaceHold er" runat="server"/>
<p />
<asp:Button ID="btnSubmit" runat="server" OnClick="btnSub mit_OnClick"
Text="Submit" />
<p />
<asp:Label ID="lblValue" runat="server" />

</asp:Content>

[Simon]

Using a masterpage prepends a string onto the front of your control
names, usually something like "ctl00_<content placeholdername >_".
(replacing <contentplaceho ldername> with the name of the
ContentPlaceHol der the control was created in.
You would then use FindControl("ct l00_whatever_yo urcontrolname") .
I have no idea why this is, it drove me nuts for a while.
Hope this helps.

Simon

[Simon]

Oops, I realized this morning that the page I was having that problem
in had never been run so I didn't realize that i was talking out of my
ass since that solution doesn't work.
What ended up working was first getting the ContentPlaceHol der control
and then using findcontrol from there:
ContentPlaceHol der mainContent;
mainContent = (ContentPlaceHo lder)Master.Fin dControl("MainF ormHolder");

DropDownList ddl =
(DropDownList)m ainContent.Find Control("contro lname");

That one ought to work for you, sorry about the idiocy :)
Simon