Set focus in TextBox after postback

Question

Set focus in TextBox after postback

I have a simple page where I want to filter a ListBox based on the values (values) in the text box - both are in the UpdatePanel.
This works correctly, however, after the postback, the text field lost focus ... so I set focus back to page_load again. Then I noticed that the cursor is now at the beginning of the text, when I want it at the end so that the user can type text, so I added the onfocus (...) attribute to the text box to return the value back to myself (see code below )

This works the first two times, but then stops focusing in the text box?

Markup

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ListTest.aspx.cs" Inherits="SalesForceTest.ListTest" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server" LoadScriptsBeforeUI="true"/>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:TextBox runat="server" ID="filter" AutoPostBack="true" onkeyup="__doPostBack(this.id, this.value)" onfocus="this.value = this.value;"  />
                <br />
                <asp:ListBox ID="AccountList" runat="server" Width="185px"></asp:ListBox>
            </ContentTemplate>
        </asp:UpdatePanel>
    </div>
    </form>
</body>
</html>

Codebehind

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

namespace SalesForceTest
{
    public partial class ListTest : System.Web.UI.Page
    {
        List<string> allAccounts = new List<string> { "2342", "3434", "2332", "3224", "7899", "8797", "3435" };

        protected void Page_Load(object sender, EventArgs e)
        {
            AccountList.Items.Clear();
            allAccounts.Where(ac => ac.StartsWith(filter.Text)).ToList().ForEach(a => AccountList.Items.Add(a));

            if (Page.IsPostBack)
            {
                if (Request.Form["__EVENTTARGET"] == filter.ID)
                {
                    ScriptManager1.SetFocus(filter);
                }
            }
        }
    }
}

Any help VERY gratefully received :)

+2

javascript asp.net

BlueChippy 27 . '10 12:29

1

VinayC · Accepted Answer · 2010-10-27T13:32:44+0000

/ , java- script. js :

function setCaretTo(obj, pos) { 
    if(obj.createTextRange) { 
        /* Create a TextRange, set the internal pointer to
           a specified position and show the cursor at this
           position
        */ 
        var range = obj.createTextRange(); 
        range.move("character", pos); 
        range.select(); 
    } else if(obj.selectionStart) { 
        /* Gecko is a little bit shorter on that. Simply
           focus the element and set the selection to a
           specified position
        */ 
        obj.focus(); 
        obj.setSelectionRange(pos, pos); 
    } 
}

: http://parentnode.org/javascript/working-with-the-cursor-position/

(document.getElementById) (textbox.value.length). script ( ScriptManager.RegisterStartupScript).

Set focus in TextBox after postback

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