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From: dodgeyb on 4 Jul 2008 17:41
I'm trying to check my html checkbox from a postback. This works fine:

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Button1.Click

Dim chk As HtmlInputCheckBox
chk = CType(FindControl("chk101228"), HtmlInputCheckBox)
chk.Checked = False
End Sub

However, if I generate the htmlcheckbox on page load event and write
it out to a literal control, the above procedure fails - control
cannot be found.

Protected Sub Form1_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Form1.Load
Me.literal1.Text = "<input runat='server' type='checkbox'
name='chk101228' id='chk101228' checked='checked' />"

End Sub

Why is this ?
Cheers
Chris
From: Scott M. on 4 Jul 2008 17:57
You aren't creating the checkbox correctly. Simply writing the code for a
checkbox and assigning it to the text of a literal control doesn't create
the object in memory.

You'd need to do this:

dim chk As New System.Web.Ui.Webcontrols.Checkbox()
chk.ID = "chkSomething"

-Scott

"dodgeyb" <chris(a)ctlsoft.com> wrote in message
news:a90b7d28-1d4e-45b3-83a2-465ea8b210d6(a)j1g2000prb.googlegroups.com...
> I'm trying to check my html checkbox from a postback. This works fine:
>
> Protected Sub Button1_Click(ByVal sender As Object, ByVal e As
> System.EventArgs) Handles Button1.Click
>
> Dim chk As HtmlInputCheckBox
> chk = CType(FindControl("chk101228"), HtmlInputCheckBox)
> chk.Checked = False
> End Sub
>
> However, if I generate the htmlcheckbox on page load event and write
> it out to a literal control, the above procedure fails - control
> cannot be found.
>
> Protected Sub Form1_Load(ByVal sender As Object, ByVal e As
> System.EventArgs) Handles Form1.Load
> Me.literal1.Text = "<input runat='server' type='checkbox'
> name='chk101228' id='chk101228' checked='checked' />"
>
> End Sub
>
> Why is this ?
> Cheers
> Chris


From: Mark Rae [MVP] on 5 Jul 2008 07:32
"dodgeyb" <chris(a)ctlsoft.com> wrote in message
news:a90b7d28-1d4e-45b3-83a2-465ea8b210d6(a)j1g2000prb.googlegroups.com...

> Why is this ?

Because Page_Load is too far into the page cycle. Try moving your dynamic
control creation code to Page_Init or Page_PreInit instead...


--
Mark Rae
ASP.NET MVP
http://www.markrae.net

From: Riki on 5 Jul 2008 13:20
dodgeyb wrote:
> I'm trying to check my html checkbox from a postback. This works fine:
>
> Protected Sub Button1_Click(ByVal sender As Object, ByVal e As
> System.EventArgs) Handles Button1.Click
>
> Dim chk As HtmlInputCheckBox
> chk = CType(FindControl("chk101228"), HtmlInputCheckBox)
> chk.Checked = False
> End Sub
>
> However, if I generate the htmlcheckbox on page load event and write
> it out to a literal control, the above procedure fails - control
> cannot be found.
>
> Protected Sub Form1_Load(ByVal sender As Object, ByVal e As
> System.EventArgs) Handles Form1.Load
> Me.literal1.Text = "<input runat='server' type='checkbox'
> name='chk101228' id='chk101228' checked='checked' />"
>
> End Sub
>
> Why is this ?
> Cheers
> Chris

A literal control containing a checkbox tag with runat="server" will not
work like a checkbox server control.
It will appear in the page as a checkbox, but it will have none of the
server side functionality, such as the possibility to find the control with
FindControl.

Instead of:
Me.literal1.Text = "<input runat='server' type='checkbox' name='chk101228'
id='chk101228' checked='checked' />"

Use a placeholder instead of a literal control, and something like:
Dim cb As New Checkbox()
cb.Id=chk101228
cb.Checked=true
Me.placeholder1.AddControl(cb)

--

Riki


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