LoadViewState not firing when Control added with AddAt

[Devin Fensterheim]

Does anyone know of an issue with a control's viewstate not persisting when dynamically adding custom controls to a web form using AddAt?

If a control is added to an HTML form directly using the HtmlForm's AddAt method (per the below code segment), then LoadViewState is never fired for the control, even if SaveViewState, which is fired, saves to the control's ViewState. However, if Add is used instead of AddAt, LoadViewState is called normally.

If anyone can offer any insight as to why this behavior occurs, I'd be grateful.

Thanks.

--
(The below code segment demonstrates the issue.)

namespace N
{
public class Demo : System.Web.UI.P age
{
protected HtmlForm Form;
private void Page_Load(objec t sender, System.EventArg s e)
{
CC s = new CC();
s.ID="sdf";
Form1.Controls. AddAt(0, s); // if Form1.Controls. Add(s), control handles state properly
}
override protected void OnInit(EventArg s e)
{
InitializeCompo nent();
base.OnInit(e);
}
private void InitializeCompo nent()
{
this.Load += new System.EventHan dler(this.Page_ Load);
}
}
public class CC : Control
{
protected override void LoadViewState(o bject savedState) // Never Called
{
ViewState["x"] = new object();
this.Controls.A dd(new LiteralControl( "Load View State"));
base.LoadViewSt ate (savedState);
}
protected override object SaveViewState()
{
ViewState["x"] = new object();
this.Controls.A dd(new LiteralControl( "Save View State Called"));
return base.SaveViewSt ate ();
}
}
}

[John Saunders]

"Devin Fensterheim" <Devin Fe*********@dis cussions.micros oft.com> wrote in
message news:28******** *************** ***********@mic rosoft.com...

Does anyone know of an issue with a control's viewstate not persisting when dynamically adding custom controls to a web form using AddAt?
If a control is added to an HTML form directly using the HtmlForm's AddAt method (per the below code segment), then LoadViewState is never fired for
the control, even if SaveViewState, which is fired, saves to the control's
ViewState. However, if Add is used instead of AddAt, LoadViewState is
called normally.
If anyone can offer any insight as to why this behavior occurs, I'd be

grateful.

I know that ASP.NET keeps track of things by the control's order within the
Controls collection. I know, for instance, that you have to add dynamic
controls in the same order on each postback. I have no reason to believe
that ASP.NET can account for cases where the order changes.
--
John Saunders
johnwsaundersii i at hotmail

[Scott G.]

Assuming you are running this code in an ASPX page, there are likely some LiteralControls (or other controls) that are in the child control collection of the Form1 control. When you use AddAt you are changing the order in which the controls are "created" and thus the ViewState can't be loaded in the Page_Load (it tries to catch up, but it can't since you manually changed the control order).

You can use the AddAt in the OnInit though, since "sdf" will come before the LiteralControls are added; or, if you added the "sdf" to a PlaceHolder things would work out.

Scott
"Devin Fensterheim" <Devin Fe*********@dis cussions.micros oft.com> wrote in message news:28******** *************** ***********@mic rosoft.com...
Does anyone know of an issue with a control's viewstate not persisting when dynamically adding custom controls to a web form using AddAt?

If a control is added to an HTML form directly using the HtmlForm's AddAt method (per the below code segment), then LoadViewState is never fired for the control, even if SaveViewState, which is fired, saves to the control's ViewState. However, if Add is used instead of AddAt, LoadViewState is called normally.

If anyone can offer any insight as to why this behavior occurs, I'd be grateful.

Thanks.

--
(The below code segment demonstrates the issue.)

namespace N
{
public class Demo : System.Web.UI.P age
{
protected HtmlForm Form;
private void Page_Load(objec t sender, System.EventArg s e)
{
CC s = new CC();
s.ID="sdf";
Form1.Controls. AddAt(0, s); // if Form1.Controls. Add(s), control handles state properly
}
override protected void OnInit(EventArg s e)
{
InitializeCompo nent();
base.OnInit(e);
}
private void InitializeCompo nent()
{
this.Load += new System.EventHan dler(this.Page_ Load);
}
}
public class CC : Control
{
protected override void LoadViewState(o bject savedState) // Never Called
{
ViewState["x"] = new object();
this.Controls.A dd(new LiteralControl( "Load View State"));
base.LoadViewSt ate (savedState);
}
protected override object SaveViewState()
{
ViewState["x"] = new object();
this.Controls.A dd(new LiteralControl( "Save View State Called"));
return base.SaveViewSt ate ();
}
}
}