Load Controls from Event?

[justsome_newbie]

This has to be simple, but I can't seem to grasp what I'm doing wrong!
I have a user control that contains a button that when clicked raises a
"AddEvent". When this fires I want the host page to add another of the
user controls to the page.

I'm tracking the number of controls to load in a textbox on the page
(wrapped in a property) and doing a for loop in the page_load. The
problem is that the addevent is processed after the load event and
therefore the number of controls is 1 behind what it should be.

Can someone please tell me what I'm doing wrong here? Or if there is a
better approach please let me know!

protected void Page_Load(Object sender, EventArgs e)
{
for (Int16 i = 1; i <= QueryBoxCount; i++)
{
QueryBox qb = (QueryBox)LoadControl("QueryBox.ascx");
qb.AddEvent += new EventHandler(QueryBox1_AddEvent);
this.Panel1.Controls.Add(qb);
}
}

protected void QueryBox1_AddEvent(Object sender, EventArgs e)
{
QueryBoxCount++;
}

private Int16 QueryBoxCount
{
get
{
return Convert.ToInt16(this.TextBox1.Text);
}
set
{
this.TextBox1.Text = value.ToString();
}
}

Thanks!

 

[justsome_newbie]

protected void QueryBox1_AddEvent(Object sender, EventArgs e)

{
QueryBoxCount++;
QueryBox qb = (QueryBox)LoadControl("QueryBox.ascx");
qb.AddEvent += new EventHandler(QueryBox1_AddEvent);
this.Panel1.Controls.Add(qb);
}

This works perfectly! For some reason I thought if I created controls
anywhere other than during the load event they would be destroyed on
post back. Shows what I know huh?

Please note you could use ViewState to store the counter internally instead
of textbox (but i quess in your current solution user can enter number of
QueryBoxes to display)

I didn't know I could use ViewState - I thought my only options where a
hidden field or a session variable. If you have time could you explain
how I could use ViewState here? I'm a complete beginner at this (I've
only ran through some basic tutorials).

Thanks again!

 

[justsome_newbie]

Wow, that's pretty easy!

Thanks!

No problem at all, Instead using TextBox to store the value between postbacks
it would be better to use viewstate, i.e.:

protected int QueryBoxCount
{
get
{
object value = ViewState["QueryBoxCount"];
return value == null ? 1 /* i'm quessing you're displaying one Query box
by default */ : (int) value;
}
set
{
ViewState["QueryBoxCount"] = value;
}
}

Done.
--
Milosz

This works perfectly! For some reason I thought if I created controls
anywhere other than during the load event they would be destroyed on
post back. Shows what I know huh?


I didn't know I could use ViewState - I thought my only options where a
hidden field or a session variable. If you have time could you explain
how I could use ViewState here? I'm a complete beginner at this (I've
only ran through some basic tutorials).

Thanks again!