PlaceHolder Question

[Guest]

hi,
How can I retrieve the Control (wucState.ascx) from the Placeholder at the
even: btn_Click:
//declaration at page
protected wucState WucState1; -- my control
....
private void Page_Load(object sender, System.EventArgs e)
{
....
WucState1 = Page.LoadControl("wucState.ascx") as wucState;
plhState.Controls.Add(WucState1);
....
}
....
private void btn_Click(object sender, System.EventArgs e)
{
WucState1 = (wucState)plhState.Controls[0]; // ERROR !!!!!! CANNOT FIND
THE CONTROL
....
}

any idea ? please with code sample.

thanx,
Oren

 

[Karl Seguin]

It isn't clear from your code whether or not you are adding the control to
your placeholder during postback. Ie, if you have the Page.LoadControl and
plhState.Controls.Add lines below in a if (!Page.IsPostBack) then things
won't work.

Also, since you've scoped WucState1 as a field (seems like it should be
private, not public, but that doesn't mater), why not just use WucState1 in
yoru click?

public class Index: Page
{
private wucState _wucState1;
private void Page_Load(object sender, System.EventArgs e)
{
_wucState1 = (wucState)Page.LoadControl("wucState.ascx");
plhState.Controls.Add(_wucState1);
if (!Page.IsPostBack)
{
//do stuff
}
}
private void btn_Click(object sender, System.EventArgs e)
{
_wucState1.Whatever //shouldn't be null, because it was recreated
in page_load on postback
}
}

Karl

 

[Guest]

Karl,
the "Page.Controls.Add" is inside "if (!Page.IsPostBack)". On the Click
event I need to retreive some data that was changed in the control.

public class Index: Page
{
private wucState _wucState1;
private System.Web.UI.WebControls.PlaceHolder plhOrder;
private void Page_Load(object sender, System.EventArgs e)
{
if (!Page.IsPostBack)
{
_wucState1 = (wucState)Page.LoadControl("wucState.ascx");
plhState.Controls.Add(_wucState1);
}
}
private void btn_Click(object sender, System.EventArgs e)
{
_wucState1 = (wucState)plhState.Controls[0]; // ERROR
}
}

It isn't clear from your code whether or not you are adding the control to
your placeholder during postback. Ie, if you have the Page.LoadControl and
plhState.Controls.Add lines below in a if (!Page.IsPostBack) then things
won't work.

Also, since you've scoped WucState1 as a field (seems like it should be
private, not public, but that doesn't mater), why not just use WucState1 in
yoru click?

public class Index: Page
{
private wucState _wucState1;
private void Page_Load(object sender, System.EventArgs e)
{
_wucState1 = (wucState)Page.LoadControl("wucState.ascx");
plhState.Controls.Add(_wucState1);
if (!Page.IsPostBack)
{
//do stuff
}
}
private void btn_Click(object sender, System.EventArgs e)
{
_wucState1.Whatever //shouldn't be null, because it was recreated
in page_load on postback
}
}

Karl

--
MY ASP.Net tutorials
http://www.openmymind.net/
http://openmymind.net/redirector.aspx?documentId=51 - Learn about AJAX!

hi,
How can I retrieve the Control (wucState.ascx) from the Placeholder at the
even: btn_Click:
//declaration at page
protected wucState WucState1; -- my control
...
private void Page_Load(object sender, System.EventArgs e)
{
...
WucState1 = Page.LoadControl("wucState.ascx") as wucState;
plhState.Controls.Add(WucState1);
...
}
...
private void btn_Click(object sender, System.EventArgs e)
{
WucState1 = (wucState)plhState.Controls[0]; // ERROR !!!!!! CANNOT FIND
THE CONTROL
...
}

any idea ? please with code sample.

thanx,
Oren

 

[Karl Seguin]

As i said (and my example showed), it must be OUTSIDE the
!Page.IsPostback....you can't find the control because on postback, it was
never recreated and added to the placeholder..

Karl
--
MY ASP.Net tutorials
http://www.openmymind.net/
http://openmymind.net/redirector.aspx?documentId=51 - Learn about AJAX!

Karl,
the "Page.Controls.Add" is inside "if (!Page.IsPostBack)". On the Click
event I need to retreive some data that was changed in the control.

public class Index: Page
{
private wucState _wucState1;
private System.Web.UI.WebControls.PlaceHolder plhOrder;
private void Page_Load(object sender, System.EventArgs e)
{
if (!Page.IsPostBack)
{
_wucState1 = (wucState)Page.LoadControl("wucState.ascx");
plhState.Controls.Add(_wucState1);
}
}
private void btn_Click(object sender, System.EventArgs e)
{
_wucState1 = (wucState)plhState.Controls[0]; // ERROR
}
}

It isn't clear from your code whether or not you are adding the control
to
your placeholder during postback. Ie, if you have the Page.LoadControl
and
plhState.Controls.Add lines below in a if (!Page.IsPostBack) then
things
won't work.

Also, since you've scoped WucState1 as a field (seems like it should be
private, not public, but that doesn't mater), why not just use WucState1
in
yoru click?

public class Index: Page
{
private wucState _wucState1;
private void Page_Load(object sender, System.EventArgs e)
{
_wucState1 = (wucState)Page.LoadControl("wucState.ascx");
plhState.Controls.Add(_wucState1);
if (!Page.IsPostBack)
{
//do stuff
}
}
private void btn_Click(object sender, System.EventArgs e)
{
_wucState1.Whatever //shouldn't be null, because it was
recreated
in page_load on postback
}
}

Karl

--
MY ASP.Net tutorials
http://www.openmymind.net/
http://openmymind.net/redirector.aspx?documentId=51 - Learn about AJAX!

hi,
How can I retrieve the Control (wucState.ascx) from the Placeholder at
the
even: btn_Click:
//declaration at page
protected wucState WucState1; -- my control
...
private void Page_Load(object sender, System.EventArgs e)
{
...
WucState1 = Page.LoadControl("wucState.ascx") as wucState;
plhState.Controls.Add(WucState1);
...
}
...
private void btn_Click(object sender, System.EventArgs e)
{
WucState1 = (wucState)plhState.Controls[0]; // ERROR !!!!!! CANNOT
FIND
THE CONTROL
...
}

any idea ? please with code sample.

thanx,
Oren