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[Solved] GridDateTimeColumn sorting bug with nested object

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Grid

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

bkelts asked on 24 Apr 2009, 10:00 PM

When a GridDateTimeColumn is bound to a nested object (e.g. DataField="SomeObject.DateField"), column sorting is broken. The sorting appears to be based on the alphanumeric order. Here is the test code below with a workaround and a workaround attempt that causes an exception:

default.aspx:

    
            <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> 
        
            <%@ Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" %> 
        
            <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> 
        
            <html xmlns="http://www.w3.org/1999/xhtml">  
        
            <head runat="server">  
        
                <title>Untitled Page</title> 
        
            </head> 
        
            <body> 
        
                <form id="form1" runat="server">  
        
                    <asp:ScriptManager ID="ScriptManager1" runat="server" /> 
        
                    <div> 
        
                        <telerik:RadGrid AllowSorting="true" AllowPaging="true" PageSize="25" ID="RadGrid1" runat="server"   
        
                            OnNeedDataSource="RadGrid1_NeedDataSource">  
        
                            <MasterTableView AutoGenerateColumns="false">  
        
                                <Columns> 
        
                                    <telerik:GridDateTimeColumn   
        
                                        DataFormatString="{0:MM/dd/yyyy}" 
        
                                        DataField="RefDate"   
        
                                        UniqueName="Column0"   
        
                                        HeaderText="ParentObj">  
        
                                    </telerik:GridDateTimeColumn> 
        
                                    <telerik:GridDateTimeColumn   
        
                                        DataFormatString="{0:MM/dd/yyyy}" 
        
                                        DataField="Dobj.RefDate1"   
        
                                        UniqueName="Column1"   
        
                                        HeaderText="ChildObj">  
        
                                    </telerik:GridDateTimeColumn> 
        
                                    <telerik:GridTemplateColumn  
        
                                        SortExpression='Dobj.RefDate1.ToString("s")' 
        
                                        UniqueName="Column2"   
        
                                        HeaderText="WorkAround1">  
        
                                        <ItemTemplate> 
        
                                            <asp:Label ID="Label1" runat="server"   
        
                                                Text='<%# String.Format("{0:MM/dd/yyyy}", Eval("Dobj.RefDate1")) %>' 
        
                                            > 
        
                                            </asp:Label> 
        
                                        </ItemTemplate> 
        
                                    </telerik:GridTemplateColumn> 
        
                                    <telerik:GridDateTimeColumn  
        
                                        SortExpression='Dobj.RefDate2.ToString("s")' 
        
                                        DataFormatString="{0:MM/dd/yyyy}" 
        
                                        DataField="Dobj.RefDate2"   
        
                                        UniqueName="Column3"   
        
                                        HeaderText="WorkAround2">  
        
                                    </telerik:GridDateTimeColumn>                    
        
                                </Columns> 
        
                            </MasterTableView> 
        
                        </telerik:RadGrid> 
        
                    </div> 
        
                </form> 
        
            </body> 
        
            </html>

default.aspx.cs:

    
            using System;  
        
            using System.Data;  
        
            using System.Configuration;  
        
            using System.Web;  
        
            using System.Web.Security;  
        
            using System.Web.UI;  
        
            using System.Web.UI.WebControls;  
        
            using System.Web.UI.WebControls.WebParts;  
        
            using System.Web.UI.HtmlControls;  
        
            using System.Collections.Generic;  
        
            public partial class _Default : System.Web.UI.Page   
        
            {  
        
                protected void Page_Load(object sender, EventArgs e)  
        
                {  
        
                }  
        
                protected void RadGrid1_NeedDataSource(object source, Telerik.Web.UI.GridNeedDataSourceEventArgs e)  
        
                {  
        
                    RadGrid1.DataSource = GetDataList();  
        
                }  
        
                protected List<PObject> GetDataList()  
        
                {  
        
                    DateTime refdt = new DateTime(2008, 12, 20);  
        
                    var dlist = new List<PObject>();  
        
                    for (int i = 1; i < 20; i++)  
        
                    {  
        
                       var dt = refdt.AddDays(i);  
        
                       dlist.Add(   
        
                                    new PObject   
        
                                    {  
        
                                        Dobj = new DObject { RefDate1 = dt, RefDate2 = dt },  
        
                                        RefDate = dt  
        
                                    }  
        
                                );  
        
                    }  
        
                    return dlist;  
        
                }  
        
            }  
        
            public class PObject  
        
            {  
        
                public DObject Dobj { get; set; }  
        
                public DateTime RefDate { get; set; }  
        
            }  
        
            public class DObject  
        
            {  
        
                public DateTime RefDate1 { get; set; }  
        
                public DateTime RefDate2 { get; set; }  
        
            }

You will notice that the first column "ParentObj" sorts fine since the bound property is part of the data object. The second column "ChildObj" is bound to a nested/child object of the main data object. This one does not sort properly. The third column "WorkAround1" is a way to work around the problem using a GridTemplateColumn and a SortExpression using .ToString("s"). Since using a GridTemplateColumn is kind of cumbersome, I thought I'd try adding the .ToString("s") to the SortExpression of a GridDateTimeColumn, but this causes an exception. This is demonstrated when trying sort the "WorkAround2" column. Although this exception should probably fixed anyway (it doesn't make sense that it works for a GridTemplateColumn and not any other kind of bound column), getting the grid to support sorting on a DateTime property of a nested object either way is fine with me.

4 Answers, 1 is accepted

answered on 27 Apr 2009, 04:29 PM

Hello Brett,

The SortExpression property of the column expects a data field and cannot be assigned to a string value. To avoid the abnormality you described so far you need to set a date type for the column. Here is a code snippet showing how to achieve this:

    
                                    <telerik:GridDateTimeColumn    
        
                                        DataFormatString="{0:MM/dd/yyyy}"  
        
                                        DataField="Dobj.RefDate1"    
        
                                        UniqueName="Column1" 
        
                                        DataType="System.DateTime" 
        
                                        SortExpression="Dobj.RefDate1" 
        
                                        HeaderText="ChildObj">   
        
                                    </telerik:GridDateTimeColumn>

Regards,
Georgi Krustev
the Telerik team

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