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How does one dynamically generate a TextBox control at run-time as a result of a button click? For each button click, I would like to create a TextBox control along with corresponding dynamic labels. I would like to do this within ASP.NET using the C# language.
431
TextBox txt = new TextBox();
txt.ID = "textBox1";
txt.Text = "helloo";
form1.Controls.Add(txt);
Label lbl = new Label();
lbl.Text = "I am a label";
form1.Controls.Add(lbl);
The following will create the controls:
var newTextbox = new Textbox();
var newLabel = new Label();
you can then set the properties etc that you want.
Then find somewhere on your page to add them to, say you have a panel called panel1, then do the following:
panel1.Controls.Add(newTextbox);
panel1.Controls.Add(newLabel);
However, doing this will not work after postback - you need to recreate the dynamic controls yourself on a postback.
Say you have the following page:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebApplication1._Default" %>
<!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></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="Button1" runat="server" Text="Button" />
</div>
</form>
</body>
</html>
When you do a postback, only the controls that are defined in the above page will be generated for you. Controls you have dynamically added need to be re-created by you (for example in the Page_Load).
To do this, the simplest way is to remember the total number of controls you have added in the viewstate, then add that many controls back in when a postback occurs.
The following should get you started:
using System;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
// Add any controls that have been previously added dynamically
for (int i = 0; i < TotalNumberAdded; ++i)
{
AddControls(i + 1);
}
// Attach the event handler to the button
Button1.Click += new EventHandler(Button1_Click);
}
void Button1_Click(object sender, EventArgs e)
{
// Increase the number added and add the new label and textbox
TotalNumberAdded++;
AddControls(TotalNumberAdded);
}
private void AddControls(int controlNumber)
{
var newPanel = new Panel();
var newLabel = new Label();
var newTextbox = new TextBox();
// textbox needs a unique id to maintain state information
newTextbox.ID = "TextBox_" + controlNumber;
newLabel.Text = "New Label";
// add the label and textbox to the panel, then add the panel to the form
newPanel.Controls.Add(newLabel);
newPanel.Controls.Add(newTextbox);
form1.Controls.Add(newPanel);
}
protected int TotalNumberAdded
{
get { return (int)(ViewState["TotalNumberAdded"] ?? 0); }
set { ViewState["TotalNumberAdded"] = value; }
}
}
}
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