Silverlight:DataGrid-Exception - Index must be within bounds

Question

Silverlight:DataGrid-Exception - Index must be within the bounds of the List. Parameter name: index after grouping using PagedCollectionView :

 When executing this code at first time it is working. second time onwards throwing exception " Index must be within the bounds of the List" . If i remove " itemListView.GroupDescriptions.Add " data is showing in the grid. Without removing this line how to solve this.. 

 

Codes are here....

 

 

 ObservableCollection<string> RepcolumnName = new ObservableCollection<string>(); 

RepcolumnName.Add(ResourceFile.SrNoLevel);

 RepcolumnName.Add(ResourceFile.EmpCodeLabel); 

RepcolumnName.Add(ResourceFile.EmployeeNameLabel); 

Binding binding = new Binding(); 

int index = 0; string bindCol = ""; 

foreach (var header in RepcolumnName) 

{  

DataGridTemplateColumn templateColumn = new DataGridTemplateColumn(); 

 templateColumn.Header = header; 

if (index == 0)

 {     bindCol = "sNo"; } 

else if (index == 1) {  bindCol = "Empno"; } 

else if (index == 2) {  bindCol = "Name"; } 

 templateColumn.HeaderStyle = LayoutRoot.Resources["headerStyle"] as Style; 

StringBuilder CellTemp = new StringBuilder(); 

CellTemp.Append("<DataTemplate "); 

CellTemp.Append("xmlns='http://schemas.microsoft.com/winfx/"); 

CellTemp.Append("2006/xaml/presentation' "); 

CellTemp.Append("xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' ");

 CellTemp.Append("xmlns:local = 'clr-namespace:System.Windows.Controls");

 CellTemp.Append(";assembly=System.Windows.Controls.Toolkit'>"); 

CellTemp.Append("<Grid>"); CellTemp.Append("<TextBlock "); 

CellTemp.Append("Text ='{Binding Path=" + bindCol + "}'  Style='{StaticResource ContentTextStyle}' IsHitTestVisible='False' ");

 CellTemp.Append("Margin='4'/>"); 

CellTemp.Append("</Grid>"); 

CellTemp.Append("</DataTemplate>");  

templateColumn.CellTemplate = (DataTemplate)XamlReader.Load(CellTemp.ToString());

 DgvEmpData.Columns.Add(templateColumn);         

 index++; } 

PagedCollectionView itemListView = new PagedCollectionView(FinalEmpList);

 DgvEmpData.ItemsSource = itemListView; 

if (itemListView.CanGroup == true) {            

  itemListView.GroupDescriptions.Add(new PropertyGroupDescription("DeptName"));

}