Collection disappear

Question

User-702247205 posted

Hello Everyone,

I have the same problem as this poster:

http://forums.asp.net/t/1731492.aspx/1?Problems+rendering+controls+collection+at+design+time

I am able to fill value with the collection editor in the form editor but I does not show at run time. Do I forget to implement a function?

I will attach the code of 3 classes in the next posts.

Also, I post the code here: http://www.hollox.net/a/HlxControl.zip

Thank you,

Have a great day!

Sébastien

Answer 1

User-702247205 posted

File: DoubleListCheck.cs

using System;
using System.Data;
using System.Configuration;
using System.Collections.Specialized;
using System.Web;
using System.Drawing;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.ComponentModel;
using System.Collections;
using System.Drawing.Design;

namespace HlxControl
{
    [ParseChildren(true)
    ,PersistChildren(false)]
    public class DoubleListCheck : WebControl, IPostBackDataHandler
    {
        private ArrayList arrSelectedValue;
        private ArrayList arrAvailableValue;

        //------------------------------------------------------------------------------------
        // C L I E N T   I N S T A N C E   N A M E
        //
        [Bindable(true)
        ,Category("Appearance")]
        public string ClientInstanceName
        {
            get
            {
                string strValue = (string)ViewState["ClientInstanceName"];
                string strResult;

                if (strValue != null)
                    strResult = strValue;
                else
                    strResult = string.Empty;
                return strResult;
            }

            set
            {
                ViewState["ClientInstanceName"] = value;
            }
        }

        //------------------------------------------------------------------------------------
        // A V A I L A B L E   V A L U E
        //
        [Bindable(true)
        ,Category("Data")
        ,Description("List of available values")
        ,Editor(typeof(DoubleListCheckEditor), typeof(UITypeEditor))
        ,PersistenceMode(PersistenceMode.InnerProperty)]
        public ArrayList AvailableValue
        {
            get
            {
                if (arrAvailableValue == null)
                    arrAvailableValue = new ArrayList();

                return arrAvailableValue;
            }
        }

        //------------------------------------------------------------------------------------
        // S E L E C T E D   V A L U E
        //
        [Bindable(true)
        ,Category("Data")
        ,Description("List of selected values")
        ,Editor(typeof(DoubleListCheckEditor), typeof(UITypeEditor))
        ,PersistenceMode(PersistenceMode.InnerProperty)]
        public ArrayList SelectedValue
        {
            get
            {
                if (arrSelectedValue == null)
                    arrSelectedValue = new ArrayList();

                return arrSelectedValue;
            }
        }

        //------------------------------------------------------------------------------------
        // C R E A T E   C H I L D   C O N T R O L S
        //
        // Override the CreateChildControls method to
        // add child controls to the Employees property when this
        // custom control is requested from a page.
        protected override void CreateChildControls()
        {
            base.CreateChildControls();
            Controls.Clear();
            CreateControlHierarchy();
            ClearChildViewState();
        }

        //------------------------------------------------------------------------------------
        // A D D   A V A I L A B L E   I T E M
        //
        public void AddAvailableItem(string strDescription, string strID, string strValue)
        {
            DoubleListCheckItem oItem = new DoubleListCheckItem(strID, strDescription, strValue);
            arrAvailableValue.Add(oItem);
        }
        
        //------------------------------------------------------------------------------------
        // A D D   S E L E C T E D   I T E M
        //
        public void AddSelectedItem(string strDescription, string strID, string strValue)
        {
            DoubleListCheckItem oItem = new DoubleListCheckItem(strID, strDescription, strValue);
            arrSelectedValue.Add(oItem);
        }

        //------------------------------------------------------------------------------------
        // A D D   R O W
        //
        private string AddRow(string strDescription, string strID, string strValue)
        {
            string strHTML = string.Empty;

            strHTML += "<tr class=\"jsDoubleListCheck_row\">";
            strHTML += "    <td><input type=\"checkbox\" /></td>";
            strHTML += "    <td>" + strDescription + "</td>";
            strHTML += "    <td><input type=\"text\" size=\"4\" maxlength=\"4\" value=\"" + strValue + "\"/></td>";
            strHTML += "    <td><input type=\"hidden\" value=\"" + strID + "\" /></td>";
            strHTML += "</tr>";

            return strHTML;
        }

        //------------------------------------------------------------------------------------
        // R E N D E R
        //
        protected string renderHtml()
        {
            // INITIALIZE
            if (ClientInstanceName == string.Empty)
                ClientInstanceName = this.ID + "_js";

            string m_ID = ClientInstanceName;
            string strHTML = string.Empty;

            // OPEN OBJECT
            strHTML += "<div class=\"jsDoubleListCheck_frame\">";

            // OPEN ROW DATA
            strHTML += "<div class=\"jsDoubleListCheck_row\">";

            // COLUMN SELECTED
            strHTML += "    <div class=\"jsDoubleListCheck_column\">";
            strHTML += "        <table id=\"" + m_ID + "_table_selected\" class=\"jsDoubleListCheck_table jsDoubleListCheck_column_selected\">";

            foreach (DoubleListCheckItem oItem in SelectedValue)
                strHTML += AddRow(oItem.Description, oItem.Value, "");

            strHTML += "        </table>";
            strHTML += "    </div>";

            // COLUMN AVAILABLE
            strHTML += "    <div class=\"jsDoubleListCheck_column\">";
            strHTML += "        <table id=\"" + m_ID + "_table_available\" class=\"jsDoubleListCheck_table jsDoubleListCheck_column_available\">";

            foreach (DoubleListCheckItem oItem in AvailableValue)
                strHTML += AddRow(oItem.Description, oItem.Value, "");

            strHTML += "        </table>";
            strHTML += "    </div>";

            // CLOSE ROW DATA
            strHTML += "</div>";

            // OPEN ROW BUTTON
            strHTML += "<div class=\"jsDoubleListCheck_row\">";

            // MOVE TO RIGHT
            strHTML += "    <div class=\"jsDoubleListCheck_column\">";
            strHTML += "        <input class=\"jsDoubleListCheck_button\" type=\"button\" value=\"Remove\" onclick=\"" + m_ID + ".moveRow('selected', 'available')\" />";
            strHTML += "    </div>";

            // MOVE TO LEFT
            strHTML += "    <div class=\"jsDoubleListCheck_column\">";
            strHTML += "        <input class=\"jsDoubleListCheck_button\" type=\"button\" value=\"Add\" onclick=\"" + m_ID + ".moveRow('available', 'selected')\" />";
            strHTML += "    </div>";

            // CLOSE ROW BUTTON
            strHTML += "</div>";

            // START - DATA
            strHTML += "<div class=\"jsDoubleListCheck_row\">";
            strHTML += "<input style=\"visibility: hidden;\" id=\"" + m_ID + "_data\" type=\"text\" />";
            strHTML += "</div>";
            // END - DATA

            // CLOSE OBJECT
            strHTML += "</div>";

            // JAVASCRIPT
            strHTML += "<script language=\"javascript\" type=\"text/javascript\">";
            strHTML += "// COMPONENT INITIALIZATION";
            strHTML += "\nvar " + m_ID + " = new jsDoubleListCheck('" + m_ID + "');";
            strHTML += "</script>";

            // RETURN
            return strHTML;
        }

        protected override void Render(HtmlTextWriter writer)
        {
            writer.Write(renderHtml());

/*
            TextBox oTextbox1;

            writer.AddAttribute("border", "1");
            writer.AddAttribute("cellpadding", "0");
            writer.AddAttribute("cellspacing", "0");
            writer.RenderBeginTag(HtmlTextWriterTag.Table);

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);

            // Label
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            oLabel.RenderControl(writer);
            writer.RenderEndTag(); //Td

            // Textbox
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            oTextbox.RenderControl(writer);
            writer.RenderEndTag(); //Td

            writer.RenderEndTag(); //Tr

            foreach (DoubleListCheckItem oItem in SelectedValue)
            {
                writer.RenderBeginTag(HtmlTextWriterTag.Tr);
                writer.RenderBeginTag(HtmlTextWriterTag.Td);

                oTextbox1 = new TextBox();
                oTextbox1.Text = oItem.Description;
                oTextbox1.RenderControl(writer);

                writer.RenderEndTag(); //Td
                writer.RenderEndTag(); //Tr
            }

            writer.RenderEndTag(); //Table
            
            //RenderContents(writer);*/
        }

        protected override void OnInit(EventArgs e)
        {
            arrSelectedValue = new ArrayList();
            arrAvailableValue = new ArrayList();

            base.OnInit(e);
            
            EnsureChildControls();
        }

        bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postValues)
        {
            string postedValue = string.Empty;
            
         /*   if (postValues[oTextbox.UniqueID] != null)
                postedValue = postValues[oTextbox.UniqueID].ToString();

            if (postedValue != Text)
            {
                Text = postedValue;
                return true;
            }*/

            return false;
        }

        void IPostBackDataHandler.RaisePostDataChangedEvent()
        {
        }
        
        //---------------------------------------------------------------------------------------------------
        // C R E A T E   C O N T R O L   H I E R A R C H Y
        //
        /// <summary>
        ///
        /// </summary>
        protected virtual void CreateControlHierarchy()
        {
           /* oTextbox = new TextBox();
            oTextbox.Text = Text;
            this.Controls.Add(oTextbox);

            oLabel = new Label();
            oLabel.Text = Title;
            this.Controls.Add(oLabel);*/

            // Register a helper hidden field
            Page.ClientScript.RegisterHiddenField(ID, "");
        }
        
        protected override void AddParsedSubObject(object o)
        {
            int i;

            i = 0;
        }

        //protected override Type
    }
}

Answer 2

User-1488931086 posted

Hi——

I'm afraid that you haven't kept the ArrayList into something like ViewState or Session, Because of this, everytime when you do a postBack and the control is re-created and all the data lost.

Plz check your CreateChildrenControls or something like this else.

Answer 3

User3866881 posted

Hello:)

protected override void OnInit(EventArgs e)

        {

            arrSelectedValue = new
ArrayList();

           
arrAvailableValue = new ArrayList();



           
base.OnInit(e);

            

            EnsureChildControls();

        }

 

In runtime the arrAvailableValue
will be assigned before this event handler and thus the assigned value is lost
by the code he added. so

Please remove the two bold statements and have a try:)

Answer 4

User-702247205 posted

Hello TimoYang and DeckerDong!

Thank you for your answers!

I implemented serialize on DoubleCheckItem (TimoYang)

I removed the code from the OnInit (DeckerDong).

Then I created a subcontrol so there is one collection that is managed per control as instructed on this blog:

www.west-wind.com/weblog/posts/2004/Jan/14/Collection-properties-in-ASPNet-Server-Controls-Building-a-TabStrip-Control

Thank you!

Sébastien