Comments on: ASP.Net Dynamic Controls (Part 4)

By: Daniel D' Aarmas

Daniel D' Aarmas — Thu, 25 Sep 2008 15:39:13 +0000

Hi, I’ve been reading your posts and are great but I have a question to help me in my development. I’m trying to add panels dynamically with out clear the previous. I mean initially I have just 1 panel with some textboxes, in the bottom of the page I have a Button to “Add a new panel”, ok i just want to click that button and render in my page a new panel without deleting de previous one, and if i have added 3 panels when i click the fourth time the button get the 4 panels rendered in the page. This can be done?? Thanks for your support!!!!

By: Jeevan

Jeevan — Tue, 16 Sep 2008 10:23:28 +0000

Hai.
Is there any posibility to generate complete grid view in dynamic means withour html source. using only code behind. if yes..
add drop downlist and checkbox from coding

By: Ming

Ming — Sun, 24 Aug 2008 20:37:08 +0000

Great Hints,
I have using one day to think about how to prevent dynamic control disappear after post back and maintenance the viewstate.
It seem i just leave it re-generate every times on Page_Load and keep the same ControlID is the easy way to solve my problem.

By: BigT

BigT — Wed, 06 Feb 2008 21:22:40 +0000

Extremely Helpful Adam!!!!
Thank you SIR! Saved me many hours of headaches…

By: Dave

Dave — Tue, 05 Feb 2008 20:22:00 +0000

Here is an example of pulling from the database and processing the ids in the save click.

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Data.SqlClient" %>

<script runat="server">

 Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
   Dim chk As CheckBox
   Dim sdr As SqlDataReader, cmd As SqlCommand, dbConn As SqlConnection

   dbConn = New SqlConnection("Data Source=localhost;Initial Catalog=Northwind")
   dbConn.Open()
   cmd = New SqlCommand("SELECT SupplierID, CompanyName FROM Suppliers ORDER BY CompanyName", dbConn)
   sdr = cmd.ExecuteReader()
   While (sdr.Read())
     chk = New CheckBox()
     chk.ID = "chk" & sdr("SupplierID")
     chk.Text = sdr("CompanyName")
     phControls.Controls.Add(chk)
     phControls.Controls.Add(New LiteralControl("<br />"))
   End While
   sdr.Close()
 End Sub

 Sub Click_Save(ByVal s As Object, ByVal e As EventArgs)
   lblMessage.Text = "Saving: "
   Dim id As String
   For Each ctl As Control In phControls.Controls
     If Left(ctl.ID, 3) = "chk" AndAlso (CType(ctl, CheckBox)).Checked Then
       id = Mid(ctl.ID, 4)
       '------------------ Process checked id's here ----------------------------
       lblMessage.Text += id & " "
     End If
   Next
 End Sub

</script>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>Dynamic Checkoxes</title>
  </head>
  <body>
  <form id="form1" runat="server">
    <div>
    <asp:Label ID="lblMessage" runat="server" />
    <br /> <br />
    <asp:PlaceHolder ID="phControls" runat="server" />
    <br /> <br />
    <asp:Button ID="btnSave" OnClick="Click_Save" Text="Save Checkboxes" runat="server" />
    </div>
  </form>
  </body>
</html>

By: sue

sue — Sat, 05 Jan 2008 17:02:34 +0000

Thanks so much for posting this; it helped me quickly solve an issue I’ve been struggling with! ~ Sue

By: Adam

Adam — Sat, 18 Aug 2007 05:01:20 +0000

C# Equivalent:

cmd.Click += new EventHandler(Button_Click);

By: sachin jain

sachin jain — Fri, 17 Aug 2007 12:28:14 +0000

Kindly tel me how to add this handler in c#(c# code)

AddHandler cmd.Click, AddressOf Button_Click

By: Alan Voir

Alan Voir — Mon, 13 Aug 2007 04:29:40 +0000

I thought Part 4 was supposed to be about AJAX? Looks like that one got ya stumped, eh? ;-)

Just as an FYI, as a writer, you really ought to refactor this series of articles. Most programmers are interested in the right way to do something, and why it’s right. You have whole articles (Part 1 and Part 2?) that essentially tell people the wrong way to do things…so why would you want someone to read that?

By: HLL

HLL — Mon, 07 May 2007 07:31:00 +0000

Hi, I read your blog. And it is really helpful. But I dont wantto create controls in a for loop in my Page_Load.
I have a case like; User selects “DataGrid” or “TextBox” or “CheckBox” from a dropdownlist and presses to a button. Every button click i need to add a textbox or a checkbox (what user selects.) to my placeholder. I could not find a solution to this.
The only solution that i found is: to add all current controls (and their values) to session after adding to placeholder. And in every page load to get controls from Session and add to page one by one..
Is there any other way? I dont want to do like that.