Control life cycle events not firing when control is invisible

TS

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Sep 29, 2008, 2:10:15 PM9/29/08

to

thru my testing it seems that neither createChildControls nor onPreRender
will run if the control is invisible, but Render still runs. Am i correct
and why does render run if the others dont?

thanks for your input~!

Allen Chen [MSFT]

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Sep 29, 2008, 10:30:28 PM9/29/08

to

Hi,

Based on my test, none of them will run if the control is invisible. Here's
my test code:
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Init(object sender, EventArgs e) {
MyControl p = new MyControl();
this.form1.Controls.Add(p);
p.Controls.Add(new TextBox());
p.Visible = false;

}
}
public class MyControl : Panel
{
protected override void CreateChildControls()
{
base.CreateChildControls();
}
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
}
protected override void Render(HtmlTextWriter writer)
{
base.Render(writer);
}
}

Could you double check it? If the Render runs on your side please send me a
demo project that can reproduce this problem. My email is
v-al...@microsoft.com.

Regards,
Allen Chen
Microsoft Online Support

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--------------------
| From: "TS" <manofs...@nospam.nospam>
| Subject: Control life cycle events not firing when control is invisible
| Date: Mon, 29 Sep 2008 13:10:15 -0500
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TS

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Sep 30, 2008, 3:23:32 PM9/30/08

to

I see the problem. After pre-render, the control was made visible, so during
createChildControls & onPreRender the control was invisible but when Render
came it was visible so render ran.

that seems a little weird behavior, seems like all or none should run.

"Allen Chen [MSFT]" <v-al...@online.microsoft.com> wrote in message
news:dAdUBSqI...@TK2MSFTNGHUB02.phx.gbl...

Allen Chen [MSFT]

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Oct 1, 2008, 10:26:13 PM10/1/08

to

Hi,

I think it's reasonable. If we set visibility on certain stage before the
Render the Render may run/not run. Here's the source code of the
Control.RenderControl method and the RenderControlInternal method. Let's
see what happens there:

protected void RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
{
if (!this.flags[0x10] && !this.flags[0x200])
{
HttpContext context = (this.Page == null) ? null :
this.Page._context;
if ((context != null) && context.TraceIsEnabled)
{
int bufferedLength = context.Response.GetBufferedLength();
this.RenderControlInternal(writer, adapter);
int num2 = context.Response.GetBufferedLength();
context.Trace.AddControlSize(this.UniqueID, num2 -
bufferedLength);
}
else
{
this.RenderControlInternal(writer, adapter);
}
}
}

private void RenderControlInternal(HtmlTextWriter writer, ControlAdapter
adapter)
{
if (adapter != null)
{
adapter.BeginRender(writer);
adapter.Render(writer);
adapter.EndRender(writer);
}
else
{
this.Render(writer);
}
}

We can see if control's flags[0x10] is true the Render method will not run.
The flags[0x10] represents the visibility of the control. To confirm this
please try following code:

Panel p = new Panel();
protected void Page_Load(object sender, EventArgs e)
{

p.PreRender += new EventHandler(p_PreRender);
p.Visible = false;//comment this line to test
this.form1.Controls.Add(p);
}
protected override void OnSaveStateComplete(EventArgs e)
{
base.OnSaveStateComplete(e);
//set a breakpoint here and check p.flags[0x10] in the watch window.
}
void p_PreRender(object sender, EventArgs e)
{

}

Please feel free to ask if you have anything unclear.

Regards,
Allen Chen
Microsoft Online Community Support

--------------------
| From: "TS" <manofs...@nospam.nospam>
| References: <eLd0j6l...@TK2MSFTNGP02.phx.gbl>
<dAdUBSqI...@TK2MSFTNGHUB02.phx.gbl>
| Subject: Re: Control life cycle events not firing when control is
invisible
| Date: Tue, 30 Sep 2008 14:23:32 -0500
| Lines: 105

| Message-ID: <#nbFMIzI...@TK2MSFTNGP05.phx.gbl>
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Allen Chen [MSFT]

unread,

Oct 8, 2008, 9:54:31 PM10/8/08

to

Hi,

Have you got the expected answer?

Regards,
Allen Chen
Microsoft Online Support

--------------------
| From: "TS" <manofs...@nospam.nospam>
| References: <eLd0j6l...@TK2MSFTNGP02.phx.gbl>
<dAdUBSqI...@TK2MSFTNGHUB02.phx.gbl>

| Subject: Re: Control life cycle events not firing when control is
invisible

| Date: Tue, 30 Sep 2008 14:23:32 -0500
| Lines: 105

| Message-ID: <#nbFMIzI...@TK2MSFTNGP05.phx.gbl>
| Newsgroups: microsoft.public.dotnet.framework.aspnet.buildingcontrols
| NNTP-Posting-Host: 168.38.106.193

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|

TS

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Oct 20, 2008, 5:10:15 PM10/20/08

to

yes, thanks

"Allen Chen [MSFT]" <v-al...@online.microsoft.com> wrote in message

news:o17u4HbK...@TK2MSFTNGHUB02.phx.gbl...