ListView: Cannot order by type 'System.Object'

I'm trying to sort a column in a ListView using Lambda Expression but, when I try to bind the result to the list view, I'm getting this error.

Here is the code, I'm trying to use.

Private Sub BindCategories(Optional ByVal SortColumn As String = Nothing, Optional ByVal SortOrder As SortDirection = SortDirection.Ascending开发者_如何学运维)
    Dim DS As IQueryable(Of DataEntities.Category) = DataEntities.Category.GetAllItems
    If Not String.IsNullOrEmpty(SortColumn) Then
        DS = Sort(Of DataEntities.Category)(DS.AsEnumerable, SortColumn, SortDirection.Ascending).AsQueryable
    End If
    lstCategories.DataSource = DS
    lstCategories.DataBind()
End Sub

and here is the code for Sort function.

Private Function Sort(Of T)(ByVal src As IEnumerable(Of T), ByVal columnName As String, ByVal orderby As SortDirection) As IEnumerable(Of T)
    Dim param = Expression.Parameter(GetType(T), "item")

    Dim sortExpression = Expression.Lambda(Of Func(Of T, Object))(Expression.Convert(Expression.[Property](param, columnName), GetType(Object)), param)

    Select Case orderby
        Case WebControls.SortDirection.Ascending
            Return src.AsQueryable().OrderBy(sortExpression)
        Case Else
            Return src.AsQueryable().OrderByDescending(sortExpression)
    End Select
End Function

The error page shows that the error occurred at lstCategories.DataBind()

Source Error:

Line 15:         End If  
Line 16:         lstCategories.DataSource = DS 
Line 17:         lstCategories.DataBind()  << **Error occurs at the point.** 
Line 18:     End Sub 
Line 19:

Stack Trace

[InvalidOperationException: Cannot order by type 'System.Object'.]

System.Data.Linq.SqlClient.QueryConverter.VisitOrderBy(Expression sequence, LambdaExpression expression, SqlOrderType orderType) +908326 System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc) +8217

System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc) +74

System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) +1003

System.Data.Linq.SqlClient.QueryConverter.ConvertOuter(Expression node) +79

System.Data.Linq.SqlClient.SqlProvider.BuildQuery(Expression query, SqlNodeAnnotations annotations) +114

System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) +132

System.Data.Linq.DataQuery1.System.Collections.Generic.IEnumerable<T>.GetEnumerator() +35 System.Collections.Generic.List1..ctor(IEnumerable1 collection) +7667686 System.Linq.Enumerable.ToList(IEnumerable1 source) +61

System.Data.Linq.Provider.BindingList.Create(DataContext context, IEnumerable1 sequence) +53

System.Data.Linq.DataQuery1.GetNewBindingList() +51

System.Data.Linq.DataQuery`1.System.ComponentModel.IListSource.GetList() +15 System.Web.UI.DataSourceHelper.GetResolvedDataSource(Object dataSource, String dataMember) +50

System.Web.UI.WebControls.ReadOnlyDataSource.System.Web.UI.IDataSource.GetView(String viewName) +41

System.Web.UI.WebControls.DataBoundControl.ConnectToDataSourceView() +128 System.Web.UI.WebControls.DataBoundControl.GetData() +4

System.Web.UI.WebControls.DataBoundControl.PerformSelect() +60

System.Web.UI.WebControls.ListView.PerformSelect() +57

System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +73

Admin_Categories.BindCategories(String SortColumn, SortDirection SortOrder) in F:\Work\Under Development\Websites\Smile\Smile-Deploy\Admin\Categories.aspx.vb:17

Admin_Categories.lstCategories_Sorting(Object sender, ListViewSortEventArgs e) in F:\Work\Under Development\Websites\Smile\Smile-Deploy\Admin\Categories.aspx.vb:65

System.Web.UI.WebControls.ListView.OnSorting(ListViewSortEventArgs e) +110 System.Web.UI.WebControls.ListView.HandleSort(String sortExpression, SortDirection sortDirection) +57

System.Web.UI.WebControls.ListView.HandleSort(String sortExpression) +52 System.Web.UI.WebControls.ListView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +268

System.Web.UI.WebControls.ListView.OnBubbleEvent(Object source, EventArgs e) +233 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37

System.Web.UI.WebControls.LinkButton.OnCommand(CommandEventArgs e) +118 System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument) +135

System.Web.UI.WebControls.LinkButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10

System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13

System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +175 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565

There is no comparison defined for the type Object. An object can be anything, how would you compare two objects without knowing what they are? For instance, you can't compare an int and a string... which is greater between 42 and "Hello world"?

So you need to know what you're comparing...