AWG Blogs

Monday, September 17, 2012

Debugging Silverlight to SSL'd SharePoint .asmx from VS

As explained here, there are a few steps you need to take to enable this scenario, i.e. to get around:

An error occurred while trying to make a request to URI 'https://machinename/_vti_bin/Lists.asmx'. This could be due to attempting to access a service in a cross-domain way without a proper cross-domain policy in place, or a policy that is unsuitable for SOAP services. You may need to contact the owner of the service to publish a cross-domain policy file and to ensure it allows SOAP-related HTTP headers to be sent. This error may also be caused by using internal types in the web service proxy without using the InternalsVisibleToAttribute attribute. Please see the inner exception for more details.

Copy the following files to C:\inetpub\wwwroot\wss\VirtualDirectories\443: crossdomain.xml:
<?xml version="1.0" encoding="utf-8"?>
<!-- The file must be configured to allow access to the service from any other domain, 
or it is not recognized by Silverlight 4.
Save the crossdomain.xml file to the root of the domain where the service is hosted. 
If, for example, the service is hosted in, 
then the file must be located at
<!DOCTYPE cross-domain-policy SYSTEM 
  <allow-http-request-headers-from domain="*" headers="SOAPAction,Content-Type"/>
<?xml version="1.0" encoding="utf-8" ?>
      <allow-from http-request-headers="*">
              <domain uri="http://*"/>
              <domain uri="https://*"/>

        <resource include-subpaths="true" path="/"></resource>
Note the subpaths="true"! Then open https://machinename/clientaccesspolicy.xml in browser (BTW verify its wellformed xml), accept the security warning, then click Certificate Error, View Certificate, then Install Certificate..., Next, then "Place all certificates in the following store", select "Trusted Root Certification Authorities", OK. After that, you should be able to F5 your Visual Studio 2010 Silverlight 5 app, and load your data from the SSL enabled Sharepoint 2007 web service. Ref1, ref2

Sunday, September 9, 2012

Set ClickMode to Press to Avoid Losing Click Event in DataGrid Column But Note Caveats

For some reason, I was losing the click event for a button in a DataGridTemplateColumn; i.e. the click event (and associated command) would not fire after editing another cell and immediately clicking the (delete) button in the far left column. Setting the ClickMode to Press (rather than the default of Release) appears to fix the issue; i.e. once that is done, the event fires, and I do not have to click Delete twice. There are a couple of steps to take in addition if the DataGrid is bound to a PagedCollectionView that you intend to Refresh() immediately, i.e. within the called Command. These are so as to avoid the error:
An exception of type 'System.InvalidOperationException' occurred in System.Windows.Data but was not handled in user code

Additional information: 'Refresh' is not allowed during an AddNew or EditItem transaction.
1) Add a GotFocus="Button_GotFocus" to the event with method:
        private void Button_GotFocus(object sender, RoutedEventArgs e)
            dataGrid1.CommitEdit(DataGridEditingUnit.Row, true);
Evidently, GotFocus fires before Click here, so it is the place to exit Edit mode.
2) Wrap the pagedCollectionView.Refresh() call in an asynchronous call:

    () =>
Evidently, the asynch call delays the refresh long enough so that the row can exit edit mode. These are workarounds that signal a compromise with MVVM and elegance in general, but until I find a better solution, it is what it is.

Use Explicit Binding to Force Update on TextChanged

If you have a TextBox inside a DataTemplate in a DataGrid, and want any TextChanged event to update the binding, set Mode=TwoWay, UpdateSourceTrigger=Explicit on the binding or else you will get an error:
"Operation is not valid due to the current state of the object."

More Notes:

Since this is an Explicit binding, you will need to hook to the event using a behavior such as Prism's UpdateTextBindingOnPropertyChanged. But since that has been made obsolete in Silverlight 5 you will need to get the class itself from the Prism code and add it to your project manually and then attach that like so:
                                <TextBox Height="23" HorizontalAlignment="Left"  
Name="textBox1" VerticalAlignment="Top" Width="120" 
Text="{Binding Invmprop, Mode=TwoWay}" >

                                        <local:MyUpdateTextBindingOnPropertyChanged />
Why is it obsolete? Because Silverlight 5 introduced UpdateSourceTrigger=PropertyChanged, which works fine in uncontained textboxes but not when they are in DataGrids (or so I've observed), so for those in DataGrids, I had to perform the above workaround.