Datagrid column sorting problem, sort looks fine visually but the ItemSource is still the same

Here is how i defined the DataGrid

                <toolkit:DataGrid 
                    Height="{Binding ElementName=parentCanvas, Path=ActualHeight}" 
                    Width="{Binding ElementName=parentCanvas, Path=ActualWidth}"
                    SelectionMode="Single" 
                    ScrollViewer.VerticalScrollBarVisibility="Auto"
                    SelectedIndex="{Binding CurrentSelectedIdx}" 
                    ItemsSource="{Binding Path=GameHostDataList, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" 
                    AutoGenerateColumns="False" 
                    x:Name="gamehostsDataGrid" 
                    IsReadOnly="True" 
                    Visibility="{Binding Path=GhListVisibility}">
                    <toolkit:DataGrid.Columns>
                        <toolkit:DataGridTextColumn Binding="{Binding FacilityId}" Header="Facility ID" MinWidth="45" Width="45*" IsReadOnly="True" SortMemberPath="FacilityId"/>
                        <toolkit:DataGridTextColumn Binding="{Binding FacilityName}" Header="Facility Name" MinWidth="100" Width="110*" IsReadOnly="True" SortMemberPath="FacilityName"/>
                        <toolkit:DataGridTextColumn Binding="{Binding GameHostIp}" Header="GH IP" MinWidth="70" Width="75*" IsReadOnly="True" SortMemberPath="GameHostIp"/>
                        <toolkit:DataGridTextColumn Binding="{Binding Status}" Header="Status" MinWidth="80" Width="85*" IsReadOnly="True" SortMemberPath="Status"/>
                        <toolkit:DataGridTemplateColumn Header="" Width="Auto" MinWidth="24">
                            <toolkit:DataGridTemplateColumn.CellTemplate>
                                <DataTemplate>
                                    <Button Margin="0" HorizontalAlignment="Center" VerticalAlignment="Center" ToolTip="Delete"
                                        Command="{StaticResource deleteGhCommand}" Focusable="False"
                                        Width="24" Height="24">
                                        <Image Source="pack://application:,,,/DesktopShell;component/Resources/Buttons/Aha-Soft/No-entry.png" />
                                    </Button>
                                </DataTemplate>
                            </toolkit:DataGridTemplateColumn.CellTemplate>
                        </toolkit:DataGridTemplateColumn>
                    </toolkit:DataGrid.Columns>
                    <e:Interaction.Triggers>
                        <e:EventTrigger EventName ="SelectionChanged">
                            <b:CommandAction Command="{Binding DisplayGhCommand}"/>
                        </e:EventTrigger>
                    </e:Interaction.Triggers>
                </toolkit:DataGrid>

The data source is as follow:

        ObservableCollectionEx<GamehostDataModel> gameHostDataList = new ObservableCollectionEx<GamehostDataModel>();

After sorting the column on the grid by clicking on the column header, the entries look sorted but when I click on the first row, the data corresponding from the unsorted list shows up. I am just wondering what is the correlation between the visual representation of the itemsource and the actual itemsource data?

Let's say for example:

Data Visually         Data Itemsource
2                     2
3                     3
1                     1

After clicking on the header to sort we have

Data Visually         Data Itemsource
1                     2
2                     3
3                     1

Is it supposed to rearrange the ref开发者_StackOverflowerence data source too?

That sounds like a bug to me. The ItemsSource should NOT be sorted by the grid.

I don't know much about the Toolkit DataGrid, but if it's like anything else in WPF, it won't sort your underlying ItemsSource. (How could it? Your ItemsSource could be a read-only IEnumerable.) Instead, it will create a collection view that wraps your ItemsSource items, and the collection view is what gets sorted. Collection views are how WPF supports sorting and grouping.

If you want to get a reference to the collection view (which contains the sorted list), see "How to: Get the Default View of a Data Collection".

i assume that your real problem is to get the right selected item. so please do NOT use

 <DataGrid SelectedIndex="{Binding CurrentSelectedIdx}" 
      <e:Interaction.Triggers>
           <e:EventTrigger EventName ="SelectionChanged">
               <b:CommandAction Command="{Binding DisplayGhCommand}"/>
           </e:EventTrigger>
      </e:Interaction.Triggers>

you should use the SelectedItem property to get what you want.

 <DataGrid SelectedItem="{Binding MyViewModelSelectedItemProperty}" ...

NO it is not supposed to do that, It is visualizing your data just assumed that you have huge data source and visualize it in a datagrid and each time you sorting that in datagrid it goes to rearrange your data source! You can do if you want by hooking up a handler.
By the way you don’t need toolkit if you can use .NET 4.0 it has datagrid control as an embedded data element.