Re: Bubbling events on a server side control

Brilliant! Thank you - after spending the past 10 hours scratching my
head, I just couldn't see it!

Dino

-----Original Message-----
From: Discussion of building .NET applications targeted for the Web
[mailto:[email protected]] On Behalf Of Efran Cobisi
Sent: Thursday, 3 April 2008 23:02
To: [email protected]
Subject: Re: [DOTNET-WEB] Bubbling events on a server side control

Adding the handler to your DropDownList's SelectedIndexChanged event in
the Render phase should bee too late for the framework to take it into
account properly.
Add it while being in the Init phase instead, just before adding the
DropDownList to the Controls collection; that should make the trick.


        protected override void OnInit(EventArgs e)
        {
            Controls.Clear();

                // Setup children's events handlers

                  this.DropDownList.SelectedIndexChanged +=3D
DropDownList_SelectedIndexChanged;

            Controls.Add(this.TextBox);
            Controls.Add(this.DropDownList);
        }


HTH

--
Efran Cobisi
http://www.cobisi.com

Dean Cleaver wrote:
> I've tried to create a control that can be either a TextBox or a
> DropDownList, but am having trouble "bubbling" the
SelectedIndexChanged
> event for the DropDownList (within an UpdatePanel if that makes any
> difference). My code is like this (snipped a bit for brevity) - is
there
> something obvious I am missing?
>
> Dino
>
>
>
> using System;
> using System.ComponentModel;
> using System.Data;
> using System.Security.Permissions;
> using System.Web;
> using System.Web.UI;
> using System.Web.UI.WebControls;
> using AjaxControlToolkit;
>
> namespace Client.Project.WebControls
> {
>     [
>     DefaultEvent("SelectedIndexChanged"),
>     DefaultProperty("Text"),
>     ToolboxData("<{0}:DetailInputBox runat=3D\"server\">
> </{0}:DetailInputBox>"),
>     ]
>     public class DetailInputBox : WebControl, IPostBackEventHandler
>     {
>         protected override void OnInit(EventArgs e)
>         {
>             Controls.Clear();
>
>             Controls.Add(this.TextBox);
>             Controls.Add(this.DropDownList);
>         }
>
>         protected override void Render(HtmlTextWriter writer)
>         {
>             if (this.IsValid || this.ReadOnly)
>                 writer.WriteLine("<div class=3D\"detailBlock\">");
>             else
>                 writer.WriteLine("<div =
class=3D\"detailBlockError\">");
>
>             writer.WriteLine("    <div class=3D\"detailInput\">");
>
>             if (this.DropDownList.Items.Count > 0)
>                 {
>                   this.DropDownList.SelectedIndexChanged +=3D
> DropDownList_SelectedIndexChanged;
>                         this.DropDownList.RenderControl(writer);
>                 }
>             else
>                 this.TextBox.RenderControl(writer);
>
>             writer.WriteLine("    </div>");
>             writer.WriteLine("    <div class=3D\"clear\"></div>");
>             writer.WriteLine("</div>");
>         }
>
>         [Browsable(false),]
>         private TextBox textBox =3D null;
>         /// <summary>
>         /// Gets or sets the required text box validator.
>         /// </summary>
>         /// <value>The required text box validator.</value>
>         private TextBox TextBox
>         {
>             get
>             {
>                 if (textBox =3D=3D null)
>                 {
>                     textBox =3D new TextBox();
>                     textBox.ID =3D this.ID + "Text";
>                 }
>                 return textBox;
>             }
>         }
>
>         [Browsable(false),]
>         private DropDownList dropDownList =3D null;
>         /// <summary>
>         /// Gets or sets the required text box validator.
>         /// </summary>
>         /// <value>The required text box validator.</value>
>         public DropDownList DropDownList
>         {
>             get
>             {
>                 if (dropDownList =3D=3D null)
>                 {
>                     dropDownList =3D new DropDownList();
>                     dropDownList.ID =3D this.ID + "List";
>                 }
>                 return dropDownList;
>             }
>         }
>
>         private bool isValid =3D true;
>         [Browsable(false)]
>         public bool IsValid
>         {
>             get { return this.isValid; }
>             set { this.isValid =3D value; }
>         }
>
>         [
>          Description("The Details Fields ValidationGroup"),
>          Category("Custom Properties"),
>         ]
>         public string ValidationGroup
>         {
>             get { return this.TextBox.ValidationGroup; }
>             set
>                 {
>                         this.TextBox.ValidationGroup =3D value;
>                         this.DropDownList.ValidationGroup =3D value;
>                 }
>         }
>
>         public ListItemCollection Items
>         {
>             get { return this.DropDownList.Items; }
>         }
>
>         public string SelectedValue
>         {
>             get { return this.DropDownList.SelectedValue; }
>         }
>
>         public int SelectedIndex
>         {
>             get { return this.DropDownList.SelectedIndex; }
>             set { this.DropDownList.SelectedIndex =3D value; }
>         }
>
>         void DropDownList_SelectedIndexChanged(object sender,
EventArgs
> e)
>         {
>             this.OnSelectedIndexChanged(e);
>         }
>
>         public event EventHandler SelectedIndexChanged;
>
>         protected virtual void OnSelectedIndexChanged(EventArgs args)
>         {
>             EventHandler thisEvent =3D this.SelectedIndexChanged;
>
>             if (thisEvent !=3D null)
>                 thisEvent(this, args);
>         }
>
>         public bool AutoPostBack
>         {
>             get { return this.DropDownList.AutoPostBack; }
>             set
>             {
>                 this.TextBox.AutoPostBack =3D value;
>                 this.DropDownList.AutoPostBack =3D value;
>             }
>         }
>
>         public void RaisePostBackEvent(string eventArgument)
>         {
>             this.OnSelectedIndexChanged(EventArgs.Empty);
>         }
>     }
> }
>
> =
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