itypedlist and sorting

[a.bek]

Hi

i have my custom ITypedList Collection that is working and display the data on the grid.

the problem comes when i try to sort the grid by clicking on a column header then

ParseException: No property or field 'Title' exists in type 'EcmsListItem']

Telerik.Web.UI.ExpressionParser.ParseMemberAccess(Type type, Expression instance) +1210

Telerik.Web.UI.ExpressionParser.ParseIdentifier() +446

Telerik.Web.UI.ExpressionParser.ParsePrimaryStart() +51

Telerik.Web.UI.ExpressionParser.ParsePrimary() +28

Telerik.Web.UI.ExpressionParser.ParseUnary() +299

Telerik.Web.UI.ExpressionParser.ParseMultiplicative() +48

Telerik.Web.UI.ExpressionParser.ParseAdditive() +53

Telerik.Web.UI.ExpressionParser.ParseComparison() +53

Telerik.Web.UI.ExpressionParser.ParseLogicalAnd() +48

Telerik.Web.UI.ExpressionParser.ParseLogicalOr() +48

Telerik.Web.UI.ExpressionParser.ParseExpression() +51

Telerik.Web.UI.ExpressionParser.ParseOrdering() +68

Telerik.Web.UI.GridDynamicQueryable.OrderBy(IQueryable source, String ordering, Object[] values) +326

Telerik.Web.UI.GridDataTableFromEnumerable.FillData35() +3375

Telerik.Web.UI.GridDataTableFromEnumerable.FillData() +807

Telerik.Web.UI.GridResolveEnumerable.Initialize() +43

Telerik.Web.UI.GridResolveEnumerable.EnsureInitialized() +32

Telerik.Web.UI.GridResolveEnumerable.get_DataTable() +25

Telerik.Web.UI.GridEnumerableFromDataView..ctor(GridTableView owner, IEnumerable enumerable, Boolean CaseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields) +187

Telerik.Web.UI.GridDataSourceHelper.CreateGridEnumerable(GridTableView owner, IEnumerable enumerable, Boolean caseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields) +149

Telerik.Web.UI.GridDataSourceHelper.GetResolvedDataSource(GridTableView owner, Object dataSource, String dataMember, Boolean caseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields) +524

Telerik.Web.UI.GridTableView.get_ResolvedDataSource() +196

Telerik.Web.UI.GridTableView.CreateChildControls(IEnumerable dataSource, Boolean useDataSource) +64

System.Web.UI.WebControls.CompositeDataBoundControl.PerformDataBinding(IEnumerable data) +59

System.Web.UI.WebControls.DataBoundControl.OnDataSourceViewSelectCallback(IEnumerable data) +111

System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +29

System.Web.UI.WebControls.DataBoundControl.PerformSelect() +149

Telerik.Web.UI.GridTableView.PerformSelect() +23

System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +70

Telerik.Web.UI.GridTableView.DataBind() +321

Telerik.Web.UI.GridSortCommandEventArgs.ExecuteCommand(Object source) +271

Telerik.Web.UI.RadGrid.OnBubbleEvent(Object source, EventArgs e) +171

System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +35

Telerik.Web.UI.GridItem.OnBubbleEvent(Object source, EventArgs e) +57

System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +35

Telerik.Web.UI.GridItem.OnBubbleEvent(Object source, EventArgs e) +147

System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +35

System.Web.UI.WebControls.LinkButton.OnCommand(CommandEventArgs e) +115

System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument) +132

System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7

System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11

System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +177

System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1746

ps the field Title is a virtual property defined by Itypedlist
any ideas?