Web Forms Custom Element

Create a User Control as follows: Click on your project and add a new item related to the image below:

AfterenteringyournameitwillopendesignandcodeforthisUserControlandyoucanaddtheelementsyouneedinbuildingsomething.

Creation:

IputaPanelandDropDownListlikethis:

<%@ControlLanguage="C#" AutoEventWireup="true" CodeBehind="WUCDropDownList.ascx.cs" Inherits="WebApplication3.WUCDropDownList" %>
<asp:Panel ID="PanelDrop" runat="server">
    <asp:DropDownList ID="DropDownList1" runat="server"></asp:DropDownList>
</asp:Panel>

In your code I made some settings for example size, as demonstrated in the code below:

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

namespace WebApplication3
{
    public partial class WUCDropDownList : System.Web.UI.UserControl
    {
        public Unit Width
        {
            get
            {
                return DropDownList1.Width;
            }
            set
            {
                DropDownList1.Width = value;
                PanelDrop.Width = value;
            }
        }
        protected void Page_Load(object sender, EventArgs e)
        {

        }
    }
}

Why? When I put this component on the screen I will have public access to this configuration and with that I can change the size that will be rendered on the screen.

Open your page in Design Mode (Example: default.aspx ) and drag the created component to the desired location.

Andinyourpropertieswillappearthatsizeconfiguration:

Note: Any property, event, or configuration should be implemented in Código do User Control