Custom Controls ASP.Net Tutorial


            using System;
using System.Web.UI.WebControls;
namespace myControls
{
    public class RequiredTextBox : CompositeControl
    {
        private TextBox input;
        private RequiredFieldValidator validator;
        public string Text
        {
            get
            {
                EnsureChildControls();
                return input.Text;
            }
            set
            {
                EnsureChildControls();
                input.Text = value;
            }
        }
        protected override void CreateChildControls()
        {
            input = new TextBox();
            input.ID = "input";
            this.Controls.Add(input);
            validator = new RequiredFieldValidator();
            validator.ID = "valInput";
            validator.ControlToValidate = input.ID;
            validator.ErrorMessage = "(Required)";
            validator.Display = ValidatorDisplay.Dynamic;
            this.Controls.Add(validator);
        }
    }
}
File: Default.aspx
<%@ Page Language="C#" Trace="true" %>
<%@ Register TagPrefix="custom" Namespace="myControls" %>
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        lblResults.Text = txtUserName.Text;
    }



    Show RequiredTextBox


    
    
            ID="lblUserName"
        Text="User Name:"
        AssociatedControlID="txtUserName"
        Runat="server" />
            ID="txtUserName"
        Runat="Server" />
    
            ID="btnSubmit"
        Text="Submit"
        Runat="server" OnClick="btnSubmit_Click" />
    
            id="lblResults"
        Runat="server" />