Hi Ext.NET,
In Page_Load i am filling MultiCombo control and selecting all the items by using MultiCombo.SelectAll() method. After this need to do another opearation based on the items selected in MultiCombo.
But its not returning any values in SelectedItems property even MultiCombo.Items also empty in the same event.

After completing loading if i refresh the page its working fine.

How to get the selected item values in pageload itself?

ASPX Code
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="Sample.WebForm1" %>

<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<!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">
    <ext:ResourceManager ID="ResourceManager1" runat="server">
    </ext:ResourceManager>
    <div>
        <ext:MultiCombo ID="MultiCombo" runat="server" DisplayField="State"
            ValueField="StateID">
            <Store>
                <ext:Store ID="storeMultiCombo" runat="server">
                    <Reader>
                        <ext:JsonReader IDProperty="StateID">
                            <Fields>
                                <ext:RecordField Name="StateID" />
                                <ext:RecordField Name="State" />
                            </Fields>
                        </ext:JsonReader>
                    </Reader>
                </ext:Store>
            </Store>
        </ext:MultiCombo>
    </div>
    </form>
</body>
</html>

CODE BEHIND
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Sample
{
 public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            List<States> states = new List<States>();
            states.Add(new States { State = "State1", StateID = 1 });
            states.Add(new States { State = "State2", StateID = 2 });
            states.Add(new States { State = "State3", StateID = 3 });

            this.MultiCombo.GetStore().DataSource = states;
            this.MultiCombo.GetStore().DataBind();

            this.MultiCombo.SelectAll();

            int n = this.MultiCombo.SelectedItems.Count; // returns 0
            int m = this.MultiCombo.Items.Count; // returns 0
        }
    }

    public class States
    {
        public string State
        {
            get;
            set;
        }
        public int StateID
        {
            get;
            set;
        }
    }
}