about FindControl ---> to find the control added by program

[Edward]

hi, everyone,
my Page_Load fill tblProducts with some TextBox.

<form runat="server">
<asp:Table id="tblProducts" runat="server"></asp:Table>
<hr>
<asp:Button id="Button1" onclick="Button1_Click" runat="server"
Text="Button"></asp:Button>
<hr>
<hr>
<asp:TextBox id="test" runat="server"/>

</form>

the method is :

TextBox getTextBox() {
TextBox txt = new TextBox();
txt.ID = "txtNum" + Convert.ToString(TextBoxCnt);
TextBoxCnt ++;

return txt;
}
when I use :
TextBox txt = (TextBox)Page.FindControl("txtNum" + Convert.ToString(i));

in the script of Button_Click, I cannot find the control. but in
Page_Load , I can get it.

And in Button_Click, TextBox "test" can be find.

How can I find the program-added controls in Button_Click?

thanks.

[S. Justin Gengo]

Edward,

My guess is that you may be adding the controls only on page load and not
post back.

For dynamically added controls to be accessible on post back they must be
added to the page again.

I have an example of this (in VB.Net, but you should get the idea) on my web
site, www.aboutfortunate.com, just go to the code library (link on the top
right of page) and search for "Dynamically add text boxes".

--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche
"Edward" <zi***@citiz.net> wrote in message
news:e4**************@TK2MSFTNGP10.phx.gbl...

hi, everyone,
my Page_Load fill tblProducts with some TextBox.

<form runat="server">
<asp:Table id="tblProducts" runat="server"></asp:Table>
<hr>
<asp:Button id="Button1" onclick="Button1_Click" runat="server"
Text="Button"></asp:Button>
<hr>
<hr>
<asp:TextBox id="test" runat="server"/>

</form>

the method is :

TextBox getTextBox() {
TextBox txt = new TextBox();
txt.ID = "txtNum" + Convert.ToString(TextBoxCnt);
TextBoxCnt ++;

return txt;
}
when I use :
TextBox txt = (TextBox)Page.FindControl("txtNum" + Convert.ToString(i));
in the script of Button_Click, I cannot find the control. but in
Page_Load , I can get it.

And in Button_Click, TextBox "test" can be find.

How can I find the program-added controls in Button_Click?

thanks.

[Kamal T.]

Hi,

A pretty good article is given in Microsoft KB "HOW TO: Dynamically Create Controls in ASP.NET by Using Visual C# .NET",

http://support.microsoft.com/default...b;EN-US;317794

Hope this link will be useful for u.

bye,

Regards,
Kamal T.

"Edward" wrote:

hi, everyone,
my Page_Load fill tblProducts with some TextBox.

<form runat="server">
<asp:Table id="tblProducts" runat="server"></asp:Table>
<hr>
<asp:Button id="Button1" onclick="Button1_Click" runat="server"
Text="Button"></asp:Button>
<hr>
<hr>
<asp:TextBox id="test" runat="server"/>

</form>

the method is :

TextBox getTextBox() {
TextBox txt = new TextBox();
txt.ID = "txtNum" + Convert.ToString(TextBoxCnt);
TextBoxCnt ++;

return txt;
}
when I use :
TextBox txt = (TextBox)Page.FindControl("txtNum" + Convert.ToString(i));

in the script of Button_Click, I cannot find the control. but in
Page_Load , I can get it.

And in Button_Click, TextBox "test" can be find.

How can I find the program-added controls in Button_Click?

thanks.

[Edward]

Thanks, Justin.

You are right. I put the code outside "postback=false".

although I got the result, but I was confused about the mechanism, How can
the textbox's value be refreshed when the second-Page_load runs ?

Thanks from heart.

"S. Justin Gengo" <sj*****@aboutfortunate.com> дÈëÏûÏ¢ÐÂÎÅ
:10*************@corp.supernews.com...

Edward,

My guess is that you may be adding the controls only on page load and not
post back.

For dynamically added controls to be accessible on post back they must be
added to the page again.

I have an example of this (in VB.Net, but you should get the idea) on my web site, www.aboutfortunate.com, just go to the code library (link on the top
right of page) and search for "Dynamically add text boxes".

--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche
"Edward" <zi***@citiz.net> wrote in message
news:e4**************@TK2MSFTNGP10.phx.gbl...

hi, everyone,
my Page_Load fill tblProducts with some TextBox.

<form runat="server">
<asp:Table id="tblProducts" runat="server"></asp:Table>
<hr>
<asp:Button id="Button1" onclick="Button1_Click" runat="server"
Text="Button"></asp:Button>
<hr>
<hr>
<asp:TextBox id="test" runat="server"/>

</form>

the method is :

TextBox getTextBox() {
TextBox txt = new TextBox();
txt.ID = "txtNum" + Convert.ToString(TextBoxCnt);
TextBoxCnt ++;

return txt;
}
when I use :
TextBox txt = (TextBox)Page.FindControl("txtNum" +

Convert.ToString(i));

in the script of Button_Click, I cannot find the control. but in
Page_Load , I can get it.

And in Button_Click, TextBox "test" can be find.

How can I find the program-added controls in Button_Click?

thanks.

[S. Justin Gengo]

Edward,

Each control's properties are gathered upon page load. .NET runs through
each control on page load and fills it's properties from the post, but it
only loops through controls that exist. So if a control isn't recreated the
control is never matched up with the post from the client.

--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche
"Edward" <zi***@citiz.net> wrote in message
news:uh**************@TK2MSFTNGP12.phx.gbl...

Thanks, Justin.

You are right. I put the code outside "postback=false".

although I got the result, but I was confused about the mechanism, How can
the textbox's value be refreshed when the second-Page_load runs ?

Thanks from heart.

"S. Justin Gengo" <sj*****@aboutfortunate.com> дÈëÏûÏ¢ÐÂÎÅ
:10*************@corp.supernews.com...

Edward,

My guess is that you may be adding the controls only on page load and not post back.

For dynamically added controls to be accessible on post back they must be added to the page again.

I have an example of this (in VB.Net, but you should get the idea) on my

web

site, www.aboutfortunate.com, just go to the code library (link on the top right of page) and search for "Dynamically add text boxes".

--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche
"Edward" <zi***@citiz.net> wrote in message
news:e4**************@TK2MSFTNGP10.phx.gbl...

hi, everyone,
my Page_Load fill tblProducts with some TextBox.

<form runat="server">
<asp:Table id="tblProducts" runat="server"></asp:Table>
<hr>
<asp:Button id="Button1" onclick="Button1_Click" runat="server" Text="Button"></asp:Button>
<hr>
<hr>
<asp:TextBox id="test" runat="server"/>

</form>

the method is :

TextBox getTextBox() {
TextBox txt = new TextBox();
txt.ID = "txtNum" + Convert.ToString(TextBoxCnt);
TextBoxCnt ++;

return txt;
}
when I use :
TextBox txt = (TextBox)Page.FindControl("txtNum" +

Convert.ToString(i));

in the script of Button_Click, I cannot find the control. but in
Page_Load , I can get it.

And in Button_Click, TextBox "test" can be find.

How can I find the program-added controls in Button_Click?

thanks.