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Editorial Team
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Asked: 2026-05-27T13:50:19+00:00

this.Controls.Add(new CheckBox{ Checked = true; }) When I add this in the page_load .

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this.Controls.Add(new CheckBox{ Checked = true; })

When I add this in the page_load. It works, it adds the checkbox and it is visible.

A little different approach: 

var button = new CheckBox{ Checked = true; } 
globals.button = button;
this.Controls.Add(button);

Globals is a class with a checkbox property on which I want to set the checkbox in the hope of retrieving it’s a data after pressing a button.

public static CheckBox button { get; set; }

However, when a button is pressed, the control has vanished of my screen and the button in my globals class has not been updated with any changes I have made to the checkbox.

How can I change the checked state of a checkbox and catch it’s current state when I perform a button.click event?

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1 Answer

  1. Editorial Team

    You must re-create dynamic controls on every postback, they wont magically re-appear because every request is a new instance of the Page class.

    See my previous post on this subject, it is using a user control but the idea is just the same.

    And another

    You must add the control before Page_Load

    I normally do it in the overridden CreateChildControls but some people use Page_Init.

    see this article

    Update

    This is a very simple way to add the checkbox dynamically, that preserves state/value when the button is clicked.

        <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Test.aspx.cs" Inherits="Test" %>

<!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">
        <asp:PlaceHolder runat="server" ID="ph"></asp:PlaceHolder>
        <asp:Button OnClick="btn_Click" runat="server" ID="btn" Text="Click Me" />

        <asp:Label runat="server" ID="lbl"></asp:Label>
    </form>
</body>
</html>

    Then Code Behind

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;


public partial class Test : Page
{
    private CheckBox MyCheckBox { get; set; }
    protected override void CreateChildControls()
    {

        this.MyCheckBox = new CheckBox() { Checked = true };
        this.ph.Controls.Add(this.MyCheckBox);
        base.CreateChildControls();
    }

    protected void btn_Click(object sender, EventArgs e)
    {
        var someValue = this.MyCheckBox.Checked;
        this.lbl.Text = someValue ? "Checked" : "Not Checked";
    }

}
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