EF6: SaveChanges overriding, changed entities not updating in WPF - wpf

Question

I have an overridden SaveChanges in my EF6 DbContext, where I set some dates and users. These changes are being saved to the database ok, but I have to quit and reopen my WPF form before they're visible there.
The SaveChanges override is:
//make sure we get all the changed objects
ChangeTracker.DetectChanges();
ObjectContext ctx = ((IObjectContextAdapter) this).ObjectContext;
//get the current user name...
//TODO needs checking that this works when via service.
string userID = System.Security.Principal.WindowsIdentity.GetCurrent().Name;
userID = userID.Substring(userID.IndexOf('\\') + 1); //remove domain
foreach (var dbEntityEntry in ctx.ObjectStateManager
.GetObjectStateEntries(EntityState.Added | EntityState.Modified)
.Where(e => e.Entity is IAuditInfo))
{
switch (dbEntityEntry.State)
{
case EntityState.Added:
((IAuditInfo) dbEntityEntry.Entity).CreatedOn = DateTime.Now;
((IAuditInfo) dbEntityEntry.Entity).CreatedBy = userID;
break;
case EntityState.Modified:
((IAuditInfo) dbEntityEntry.Entity).LastUpdatedOn = DateTime.Now;
((IAuditInfo) dbEntityEntry.Entity).LastUpdatedBy = userID;
break;
case EntityState.Deleted:
case EntityState.Detached:
case EntityState.Unchanged:
default:
break;
}
}
ctx.SaveChanges(SaveOptions.None);
return base.SaveChanges();
My WPF XAML:
<Page.Resources>
<CollectionViewSource x:Key="actionStatusesViewSource"
d:DesignSource="{d:DesignInstance my:ActionStatus, CreateList=True}" />
</Page.Resources>
<Grid DataContext="{StaticResource actionStatusesViewSource}"
Margin="5">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<DataGrid Grid.Row ="1"
AutoGenerateColumns="False"
EnableRowVirtualization="True"
ItemsSource="{Binding}"
Name="actionStatusesDataGrid"
RowDetailsVisibilityMode="VisibleWhenSelected"
VerticalAlignment="Top"
ClipboardCopyMode="IncludeHeader">
<DataGrid.Columns>
<DataGridTextColumn x:Name="idColumn"
Binding="{Binding Path=Id, Mode=TwoWay}"
Header="Id"
Width="SizeToHeader" />
<DataGridTextColumn x:Name="nameColumn"
Binding="{Binding Path=Name, Mode=TwoWay}"
Header="Name"
Width="256" />
<DataGridTemplateColumn x:Name="validFromColumn"
Header="Valid From"
Width="128">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<DatePicker SelectedDate="{Binding Path=ValidFrom, Mode=TwoWay, ValidatesOnExceptions=true, NotifyOnValidationError=true}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn x:Name="validToColumn"
Header="Valid To"
Width="128">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<DatePicker SelectedDate="{Binding Path=ValidTo, Mode=TwoWay, ValidatesOnExceptions=true, NotifyOnValidationError=true}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn x:Name="lastUpdatedByColumn"
Binding="{Binding Path=LastUpdatedBy, Mode=TwoWay}"
Header="Updated By"
Width="SizeToHeader" />
<DataGridTextColumn x:Name="lastUpdatedOnColumn"
Binding="{Binding Path=LastUpdatedOn, Mode=TwoWay, StringFormat=\{0:dd/MM/yyyy HH:mm\}}"
Header="Updated On"
Width="SizeToCells" />
<DataGridTextColumn x:Name="createdByColumn"
Binding="{Binding Path=CreatedBy, Mode=TwoWay}"
Header="Created By"
Width="SizeToHeader" />
<DataGridTextColumn x:Name="createdOnColumn"
Binding="{Binding Path=CreatedOn, Mode=TwoWay, StringFormat=\{0:dd/MM/yyyy HH:mm\}}"
Header="Created On"
Width="SizeToCells" />
</DataGrid.Columns>
</DataGrid>
And finally my load and save code:
private RegRiskContext context; //our model context (via the service)
private DataServiceCollection<ActionStatus> actionStatusBinding; //our bound collection
private CollectionViewSource viewSource; //the view source for the collection
private delegate void OperationResultCallback(); //delegate for the dispatcher invokes
public AdminActionStatus()
{
InitializeComponent();
}
private void Page_Loaded(object sender, RoutedEventArgs e)
{
//get the CollectionViewSource object
viewSource = ((CollectionViewSource) (this.FindResource("actionStatusesViewSource")));
try
{
UIHelper.ProgressBarRun(true);
//initialise the context
context = new RegRiskContext(new Uri(RegRiskSettings.Default.ServiceURL));
//create a query ready for the async operation
DataServiceQuery<ActionStatus> dsq = context.ActionStatuses;
try
{
dsq.BeginExecute(OnQueryCompleted, dsq);
}
catch (DataServiceClientException ex)
{
MessageBox.Show(ex.ToString());
}
/* synchronous version
* note the freeze when opening the window
var q = context.ActionStatuses.OrderBy(f => f.Id);
DataServiceCollection<ActionStatus> actionStatuses = new DataServiceCollection<ActionStatus>(q);
viewSource.Source = actionStatuses;
*/
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void OnQueryCompleted(IAsyncResult result)
{
// Get the original query object from the state cache.
DataServiceQuery<ActionStatus> query = (DataServiceQuery<ActionStatus>) result.AsyncState;
//use Dispatcher to ensure we're on the UI thread!
this.Dispatcher.BeginInvoke(new OperationResultCallback(delegate
{
try
{
//instantiate the binding collection using results of the query
actionStatusBinding = new DataServiceCollection<ActionStatus>(query.EndExecute(result));
//set the Source to the collection
viewSource.Source = actionStatusBinding;
UIHelper.ProgressBarRun(false);
}
catch (DataServiceRequestException ex)
{
MessageBox.Show(ex.ToString());
}
}), null);
}
private void saveButton_Click(object sender, RoutedEventArgs e)
{
try
{
UIHelper.ProgressBarRun(true);
context.BeginSaveChanges(OnSaveChangesCompleted, null);
}
catch (DataServiceClientException ex)
{
MessageBox.Show(ex.ToString());
}
}
private void OnSaveChangesCompleted(IAsyncResult result)
{
// Use the Dispatcher to ensure that the operation returns in the UI thread.
this.Dispatcher.BeginInvoke(new OperationResultCallback(delegate
{
try
{
// Complete the save changes operation.
context.EndSaveChanges(result);
viewSource.View.Refresh();
UIHelper.ProgressBarRun(false);
}
catch (DataServiceRequestException ex)
{
MessageBox.Show(ex.ToString());
}
}), null);
}
I don't know if its because my SaveChanges override needs to notify somehow? or if its the WPF thats wrong?
There is a WCF DataServices layer between the WPF and the EF, but that looks 'straightforward' enough, and I can't see what I could even change there.

Answer 1

Found a solution, not entirely sure why it fixes it though, so any expanded explanation would be gratefully received.
My WCF DataService class is simple:
public class RegRiskService : EntityFrameworkDataService<BOI.RegRisk.Model.RegRiskContext>
{
// This method is called only once to initialize service-wide policies.
public static void InitializeService(DataServiceConfiguration config)
{
// TODO: set rules to indicate which entity sets and service operations are visible, updatable, etc.
config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3;
//snip access stuff
}
}
It was the protocol version, it was defaulted to v2, changing it to v3 seems to have resolved the issue. My WPF datagrid now updated with the changes made in the SaveChanges override.
Again there's a caveat for anybody with the same original issue, I've been looking at this issue for a while, so there is a chance there was something else I changed that was the actual root cause!