Creating Dynamic Controls, also preserve already created controls Samples and examples

Normally when you create a control dynamically means at runtime, on the next page load you will loose that control, that control will be no longer exists, in this example I am try to explain how we can store that controls and get them back.

Create a Web Application and Add one button to it.

In the page load add following code, in the following code I am creating a object of Control Collection and keeping it in the Session.


        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                ControlCollection ctrls = new ControlCollection(Page.Form);
                Session["Controls"] = ctrls;
            }
        }

Now Doble click on button1 and add following code in Button1_Click event.

Here in this code I am storing all the controls created into control collection and saving into session.


 protected void Button2_Click(object sender, EventArgs e)
        {
            //Creating object of Control Collection
            ControlCollection ctrls = null;
            //Checking if Object is already present in session or not
            // If not present create again.
            if (Session["Controls"] != null)
            {
                ctrls = (ControlCollection)Session["Controls"];
            }
            else
            {
                ctrls = new ControlCollection(Page.Form);
            }
            //Using random number to avoid conflict in control names
            Random r = new Random();
            //Creating label control
            Label l1 = new Label();
            l1.ID = "Label" + r.NextDouble().ToString();
            l1.Text = "Some Text";
            //Adding label control to control collection
            ctrls.Add(l1);
            //Creating text control
            TextBox txt = new TextBox();
            txt.ID = "TextBox" + r.NextDouble().ToString();
            //Adding text control to control collection
            ctrls.Add(txt);
            //Now add controls whic are present in 
            //Control collection to form
            foreach (Control ctrl in ctrls)
            {
                Page.Form.Controls.Add(ctrl);
            }
            //Save the control back to session.
            Session["Controls"] = ctrls;
        }

now we are ready with code jusr build, run and test

Hope this helps.

SatishKumar J
Microsoft MVP(ASP.NET)

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