Server Control with Child Control, dynamic created, retain control

public class RelatedPublicationFilesSave : Control
{
    protected HiddenField _test;

    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        _test= new HiddenField();
        _test.ID = "_test";
        this.Controls.Add(_test);
    }
     protected override void OnLoad(EventArgs e)
    {
        _RelatedPublicationFilesSave =
            this.FindControlById("_test") as HiddenField;
        Log.Debug("_test.Value: " + _test.Value);
    }
}

 the point is that OnInit happens before the page parses itself, so creating the control there without passing any value to it with the same ID will eventually render the same "name" property (UniqueID) and thus assigning the right values from the request.

 lets do another example, answering this, where we want to add a table with dynamic Checkboxes count.

 we start by creating a server control, creating and declaring all controls in the OnInit, rendering the HTML in the RenderControl

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication3
{
   public class DynamicCbs : Control
   {
      public int CtrlsCount { get; set; }
      public List<CheckBox> lstCheckBoxs;

      /// decleration of controls must be in the OnInit since the next stage of the page life cycle is to connect whatever came back from the client to the server
      protected override void OnInit(EventArgs e)
      {
           base.OnInit(e);
           lstCheckBoxs = new List<CheckBox>();
           for (int i = 0; i < CtrlsCount; i++)
           {
              string id = "DynamicCbs" + i;
              CheckBox cbx = new CheckBox()
              {
                 ID = id,
                 Text = "i am " + id
              };
              lstCheckBoxs.Add(cbx);
              //add controls to control tree
              this.Controls.Add(cbx);
           }
       }

       /// here you must build ur html
       public override void RenderControl(HtmlTextWriter writer)
       {
           writer.RenderBeginTag(HtmlTextWriterTag.Table);
           writer.RenderBeginTag(HtmlTextWriterTag.Thead);
           foreach (var cbx in lstCheckBoxs)
           {
              writer.RenderBeginTag(HtmlTextWriterTag.Th);
              cbx.RenderControl(writer);
              writer.RenderEndTag();
           }
           writer.RenderEndTag();//thead
           writer.RenderEndTag();//table
       }
    }
}
in the .aspx file

<%@ Register TagPrefix="my" Namespace="WebApplication3" Assembly="WebApplication3" %>
<my:DynamicCbs ID="Dynamicus" runat="server" CtrlsCount="10"></my:DynamicCbs>
<asp:Button runat="server" Text="Button" />
<div>
   <h1>true controls:</h1>
   <div runat="server" id="txt"></div>
</div>

in our .aspx.cs Page_Load
           
foreach (var cbx in Dynamicus.lstCheckBoxs)
{
  if (cbx.Checked) {
     txt.InnerHtml += cbx.ID + "<br/>";
  }
}
results:

















Comments

Post a Comment

Popular posts from this blog

OverTheWire[.com] Natas Walkthrough - JUST HINT, NO SPOILERS

game portal: http://overthewire.org/wargames/natas/ PASSWORDS for each level are stored in /etc/natas_webpass/natasX I made this walkthrough for people like me, i needed some help, but didnt want the spoiler, so here i will give you all the information needed to pass each level, yet not the solution. For levels needed custom web request i made a different post for powershell and javascript  with how-to's, since is a piece of learning for itself, and also for those of us that play at work and have only powershell at their hands. Although its not a complete spoiler there, its quite most of the solution so try yourself 1st. Natas The Natas game is from basic to advances web hacking. Every few levels is about whole new exploitation (with some harder ones doing comeback later), so a lot of learning. If you're new, you're the reason i am writing so much even for the 1st level, just please google EVERY topic you see, since in the following levels i assume you know the ...
Read more

Asp.Net Ending Response options, Response.End() vs CompleteRequest()

this blog is for any1 who get the ThreadAbortException when caling Response.End(), and then tried the other options such as HttpContext.Current.ApplicationInstance.CompleteRequest() and found out that there was no replacement. i'll start with the bottom line: if you want to stop right now your response and send it as is you dont have any other option other than Response.End(), period and it's the right thing to throw that EX in that case. the answer is its because there is the "HTTP pipeline" and the "Asp.Net pipeline", and CompleteRequest() cuts the HTTP pipeline but not the Asp.Net one so everything that is from handlers forwars (including all page events) continues but your part, the asp one, stays in your hands so that no information will be lost, so ur suppose to manage your code currectly, since information lost is really a bad thing, although in most cases we use Response.End() we know what we are losing and we want it. see this short article ab...
Read more

SOLVED The item could not be indexed successfully because the item failed in the indexing subsystem

if you got an error like this The item could not be indexed successfully because the item failed in the indexing subsystem. ( The item could not be indexed successfully because the item failed in the indexing subsystem.; Failed to recover content group; Aborting insert of item in Link Database because it was not inserted to the Search Index.; ; SearchID = 04081656-B51B-4DCD-96D4-6DB2D2CEEEE7 ) as well as these: The item could not be indexed successfully because the item failed in the indexing subsystem. ( The item could not be indexed successfully because the item failed in the indexing subsystem.; Caught exception when preparing generation GID[7]: (Previous generation (last=GID[6], curr=GID[7]) is still active. Cannot open GID[7]); Aborting insert of item in Link Database because it was not inserted to the Search Index.; ; SearchID = 92EB0180-C086-4853-BED8-F4878D9748AD ) the solution for me was to clear configuration cache (PS)  and then restart SP Search Services. THX ...
Read more