Improve company productivity with a Business Account.Sign Up

x
?
Solved

Problem: after the parent DataList.DataBind(), changing controls' value within the dataList failed.

Posted on 2004-10-13
3
Medium Priority
?
272 Views
Last Modified: 2010-04-15
Hi Dear Sir/Madam,
I am a web developer writing web applications in C#, now I have a problem with my page and am stuck, :(

I have a aspx page which has a datalist like following. It has multiple server controls, like textbox, dropdownlist.
------------------------------------------------------------------------
<asp:DataList id="customerInfoDetailDataList" runat="server" DataKeyField="CustomerID" OnItemCommand="DLCommandHandler"
OnItemDataBound="customerInfoDetailDataList_ItemDataBound">
<ItemTemplate>
<asp:TextBox id="companyTextBox" runat="server" CssClass="formelements" Text='<%# DataBinder.Eval(Container.DataItem, "CompanyName") %>' size="25"/></td>
....
------------------------------------------------------------------------
in the pageload method of the backend C# file, I write:
------------------------------------------------------------------------
private void Page_Load(object sender, System.EventArgs e)
{
if(!IsPostBack)
{                        
generalInfoDataSet = GetCustomerGeneralInfo(pickedCustomerID);                        
customerInfoDetailDataList.DataSource = generalInfoDataSet.Tables[0];
customerInfoDetailDataList.DataBind();

TextBox cityTextBox = (TextBox)customerInfoDetailDataList.Items[0].FindControl("cityTextBox");
cityTextBox.Text = "test";
cityTextBox.DataBind();
customerInfoDetailDataList.DataBind();

DropDownList stateDropDownList = (DropDownList)customerInfoDetailDataList.Items[0].FindControl("stateDropDown");
stateDropDownList.DataSource = dropDownTableDataSourceTable;
stateDropDownList.DataBind();
------------------------------------------------------------------------

Only customerInfoDetailDataList dataBind works, neither changing the contained textbox value or dropdownlist databind works, although through debug lines, those codes are executed.

Does anyone has any idea why it's happening? I am having similar problems with other datalist, but datagrid works fine.

Any help is greatly appreciated!
GotVMail.
0
Comment
Question by:gvmdevelopment
1 Comment
 
LVL 3

Accepted Solution

by:
Realmrat earned 1000 total points
ID: 12305662
Let me ask a question.  Are you trying to populate the DropDownList from values from a Database?  Here's an implimentation:

                       Codebehind
|-----------------------------------------------------------------------------------------
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.Odbc;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace CCTest
{
      /// <summary>
      /// Summary description for Test2.
      /// </summary>
      public class Test2 : System.Web.UI.Page
      {
        protected System.Web.UI.WebControls.DataList DataList1;
   
            private void Page_Load(object sender, System.EventArgs e)
            {
            if( !IsPostBack )
            {
                DataSet customerData = LoadCustomersFromDatabase();
                DataList1.DataSource = customerData;
                DataList1.DataBind();
            }
            }

        protected void OnDataList_Load(object sender, System.EventArgs e)
        {
            // Get the Data
            DataSet stateData = LoadStatesFromDatabase();

            // Iterate through all rows within the DataList
            for (int i=0; i < DataList1.Items.Count; i++)
            {
                // Find the DropDownList Control
                DropDownList stateDropDownList = (DropDownList)DataList1.Items[i].FindControl("StateDropDownList");

                // This will add the column value to the DropDownList
                foreach( DataRow row in stateData.Tables[0].Rows )
                {
                    stateDropDownList.Items.Add( row["state"].ToString() );
                }
                // Bind the Data to the Control
                stateDropDownList.DataBind();
            }
        }

        private DataSet LoadCustomersFromDatabase()
        {
            //Connection String
            string connectionString = @"...";

            //Command String
            string commandString = @"SELECT * FROM test_customers";

            OdbcDataAdapter dataAdapter = new OdbcDataAdapter(commandString,connectionString);

            DataSet myDataSet = new DataSet();
            dataAdapter.Fill (myDataSet);
            return myDataSet;
        }

        private DataSet LoadStatesFromDatabase()
        {
            //Connection String
            string connectionString = @"...";

            //Command String
            string commandString = @"SELECT state FROM test_states ORDER BY state";

            OdbcDataAdapter dataAdapter = new OdbcDataAdapter(commandString,connectionString);

            DataSet myDataSet = new DataSet();
            dataAdapter.Fill (myDataSet);
            return myDataSet;
        }

            #region Web Form Designer generated code
            override protected void OnInit(EventArgs e)
            {
                  //
                  // CODEGEN: This call is required by the ASP.NET Web Form Designer.
                  //
                  InitializeComponent();
                  base.OnInit(e);
            }
            
            /// <summary>
            /// Required method for Designer support - do not modify
            /// the contents of this method with the code editor.
            /// </summary>
            private void InitializeComponent()
            {    
            this.DataList1.Load += new System.EventHandler(this.OnDataList_Load);
            this.Load += new System.EventHandler(this.Page_Load);

        }
            #endregion
      }
}



                       Page.aspx
|-----------------------------------------------------------------------------------------
<%@ Page language="c#" Codebehind="Test2.aspx.cs" AutoEventWireup="false" Inherits="CCTest.Test2" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
    <HEAD>
        <title>Test2</title>
        <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
        <meta name="CODE_LANGUAGE" Content="C#">
        <meta name="vs_defaultClientScript" content="JavaScript">
        <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
    </HEAD>
    <body>
        <form id="Form1" method="post" runat="server">
            <asp:DataList id="DataList1" runat="server" DataKeyField="CustomerID">
                <ItemTemplate>
                    <table>
                        <tr>
                            <td align="right">
                                CustomerID:
                            </td>
                            <td><%# DataBinder.Eval(Container.DataItem, "CustomerID") %></td>
                        </tr>
                        <tr>
                            <td align="right">
                                Name:
                            </td>
                            <td><%# DataBinder.Eval(Container.DataItem, "CustomerName") %></td>
                        </tr>
                        <tr>
                            <td align="right">City:</td>
                            <td><%# DataBinder.Eval(Container.DataItem, "City") %></td>
                        </tr>
                        <tr>
                            <td align="right">State:</td>
                            <td>
                                <asp:DropDownList ID="StateDropDownList" Runat="server"></asp:DropDownList>
                            </td>
                        </tr>
                    </table>
                </ItemTemplate>
                <SeparatorTemplate>
                    <hr>
                </SeparatorTemplate>
            </asp:DataList>
        </form>
    </body>
</HTML>


I think that's what you were looking for ... =]

 - Joe
0

Featured Post

What Kind of Coding Program is Right for You?

There are many ways to learn to code these days. From coding bootcamps like Flatiron School to online courses to totally free beginner resources. The best way to learn to code depends on many factors, but the most important one is you. See what course is best for you.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Introduction Hi all and welcome to my first article on Experts Exchange. A while ago, someone asked me if i could do some tutorials on object oriented programming. I decided to do them on C#. Now you may ask me, why's that? Well, one of the re…
Calculating holidays and working days is a function that is often needed yet it is not one found within the Framework. This article presents one approach to building a working-day calculator for use in .NET.
Did you know PowerShell can save you time with SaaS platforms? Simply leverage RESTfulAPIs to build your own PowerShell modules. These will kill repetitive tickets and tabs, using the command Invoke-RestMethod. Tune into this webinar to learn how…
Watch the software video of Kernel Import PST to Office 365 tools which can easily import PST and OST files to Office 365 for bulk mailboxes. The process of migration is simple and user can map source and destination mailboxes and easily import data…

589 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question