Sorting problem with Radgrid

[Tabassum]

Hi,

 When I click on a column of a radgrid, grid.SortExpressions.GetSortString()  returns NULL on first click. On second click it returns clicked column name ASC on thrid click it returns clicked column DESC and on next click it returns NULLagain.

 Can you please advise me what is wrong here. Need to correct it ASAP.

My Code look like this:


<telerik:RadGrid ID="HmsCasesGridView" runat="server" AutoGenerateColumns="false" AllowSorting="true" Skin="Default" AllowPaging="true" AllowCustomPaging="true" PageSize="20">
<MasterTableView>
<Columns>
<telerik:GridHyperLinkColumn DataTextField="OpenActionTitle" DataNavigateUrlFields="EmployeeID,CaseID" DataNavigateUrlFormatString="../Forms/Case.aspx?EmployeeID={0}&CaseID={1}" Display="true">
</telerik:GridHyperLinkColumn>
<telerik:GridBoundColumn DataField="CaseID" />
<telerik:GridBoundColumn DataField="EmployeeID" />
<telerik:GridBoundColumn DataField="Name" />
<telerik:GridBoundColumn DataField="NextPlannedDate" DataFormatString="{0:dd.MM.yyyy}" />
<telerik:GridBoundColumn DataField="NextActivityName" />                
</Columns>
</MasterTableView>
</telerik:RadGrid>

Thank you,
Tabassum

[Pavlina]

Hello,

How is the grid populated? In case you are using simple databinding calling DataBind() switch to advanced databanding through NeedDataSource as shown in the example below and let me know if the same problem still persists.
http://demos.telerik.com/aspnet-ajax/grid/examples/data-binding/simple-vs-advanced/defaultcs.aspx

Regards,
Pavlina
Telerik