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[Solved] Disable LoadOnDemand based on size of recordset

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ComboBox

This is a migrated thread and some comments may be shown as answers.

4 Answers, 1 is accepted

Accepted

answered on 25 Jan 2010, 01:31 PM

Sorry, Page_Init :)

    
            <%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %> 
        
            <!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"> 
        
                <telerik:RadScriptManager ID="RadScriptManager1" runat="server"> 
        
                </telerik:RadScriptManager> 
        
                <telerik:RadComboBox ID="combo" runat="server" EnableLoadOnDemand="true"  
        
                    DataTextField="submissionid" DataValueField="submissionid" EnableVirtualScrolling="true"  
        
                                    DropDownWidth="300" Width="300" Height="300"  
        
                                    onitemsrequested="combo_ItemsRequested" /> 
        
                </form> 
        
            </body> 
        
            </html>

    
            using System; 
        
            using System.Collections.Generic; 
        
            using System.Linq; 
        
            using System.Web; 
        
            using System.Web.UI; 
        
            using System.Web.UI.WebControls; 
        
            using System.Data.SqlClient; 
        
            using System.Data; 
        
            using System.Web.Security; 
        
            using System.Configuration; 
        
            using DataSet1TableAdapters; 
        
            using Telerik.Web.UI; 
        
            public partial class _Default : System.Web.UI.Page  
        
            { 
        
                private const int ItemsPerRequest = 10; 
        
                protected void Page_Init(object sender, EventArgs e) { 
        
                    //If the rows returned are less than 3000 
        
                    if (GetData().Rows.Count < 3000) { 
        
                        //Disable the LoadOnDemand Stuff 
        
                        combo.EnableVirtualScrolling = false; 
        
                        combo.ItemsRequested -= new RadComboBoxItemsRequestedEventHandler(combo_ItemsRequested); 
        
                        combo.EnableLoadOnDemand = false; 
        
                        //Bind the combo to the data 
        
                        combo.DataSource = _data; 
        
                        combo.DataBind(); 
        
                    } 
        
                } 
        
                /// <summary> 
        
                /// Load on Demand Event 
        
                /// </summary> 
        
                protected void combo_ItemsRequested(object o, Telerik.Web.UI.RadComboBoxItemsRequestedEventArgs e) { 
        
                    ss_submissionResponseTableAdapter tableAdapter = new ss_submissionResponseTableAdapter(); 
        
                    DataSet1.ss_submissionResponseDataTable dataTable = this.GetData(); 
        
                    int itemOffset = e.NumberOfItems; 
        
                    int endOffset = Math.Min(itemOffset + ItemsPerRequest, dataTable.Rows.Count); 
        
                    e.EndOfItems = endOffset == dataTable.Rows.Count; 
        
                    for (int i = itemOffset; i < endOffset; i++) { 
        
                        DataSet1.ss_submissionResponseRow row = dataTable.Rows[i] as DataSet1.ss_submissionResponseRow; 
        
                        combo.Items.Add(new RadComboBoxItem(row.submissionid.ToString(), row.submissionid.ToString())); 
        
                    } 
        
                    e.Message = GetStatusMessage(endOffset, dataTable.Rows.Count); 
        
                } 
        
                /// <summary> 
        
                /// Get the Data, probably pass in a text value like the Demo  
        
                /// </summary> 
        
                private DataSet1.ss_submissionResponseDataTable _data = null; 
        
                private DataSet1.ss_submissionResponseDataTable GetData() { 
        
                    if (_data == null) { 
        
                        ss_submissionResponseTableAdapter tableAdapter = new ss_submissionResponseTableAdapter(); 
        
                        DataSet1.ss_submissionResponseDataTable dataTable = null; 
        
                        try { 
        
                            _data = tableAdapter.GetData(); 
        
                        } catch (Exception ex) { 
        
                        } finally { 
        
                            tableAdapter.Dispose(); 
        
                        } 
        
                    } 
        
                    return _data; 
        
                } 
        
                /// <summary> 
        
                /// Status Event 
        
                /// </summary> 
        
                private static string GetStatusMessage(int offset, int total) { 
        
                    if (total <= 0) 
        
                        return "No matches"; 
        
                    return String.Format("Items <b>1</b>-<b>{0}</b> out of <b>{1}</b>", offset, total); 
        
                } 
        
            }