I’ve given away most of my invites over Twitter but there are a few remaining though. So if you’d like a wave invite drop me a mail or leave a comment with your email address.

One tip I’ve found useful on my first day is to see public waves using with:public. The list is like a fire hose so I usually add some criteria e.g. ‘sharepoint with:public’ to see all public sharepoint waves.

Here’s one quick way that does not not involve writing any additional code.

Step 1: Start off by creating a class that will represent each checked list item in the list box. Obviously if you already have your data item all you need to ensure is that it has a boolean property to store the Checked/Unchecked flag.

public class CheckedListItem
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsChecked { get; set; }
}

Step 2: Create the list item that will be bound to the list box. I called my list AvailablePresentationObjects.

public List<CheckedListItem> AvailablePresentationObjects;

Step 3: The last step is to create the actual checked list box. I created a list box and used the HierarchicalDataTemplate to hold the CheckBox. The Name and the IsChecked property are then bound to the checkbox.

<ListBox ItemsSource="{Binding AvailablePresentationObjects}" >
    <ListBox.ItemTemplate>
        <HierarchicalDataTemplate>
            <CheckBox Content="{Binding Name}" IsChecked="{Binding IsChecked}"/>
        </HierarchicalDataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

And walla!

Now the IsChecked property will reflect the value in the UI and vice versa. If you need real-time notification when someone checks/unchecks then you simply need to raise the PropertyChanged event in the CheckedListItem class.

Let’s build a better, peaceful Sri Lanka.

I racked my brain trying to figure out how to add ETags to a xap file and yet keep the deployment simple. The answer though is unbelievably simple in this case. Update your AssemblyVersion when compiling. That’s it. IIS takes care of sending the update through to all the browsers.

BTW the silverlight.net forums are a gem for figuring out answers to silverlight problems.

The solution was to make a call to change the default schema using the ALTER SESSION call with this code.

        /// <summary>

        /// Sets the schema to use if one is configured.

        /// </summary>

        public static void SetSchema()

        {

            var schema = ConfigurationManager.AppSettings["SchemaName"];

            if (string.IsNullOrEmpty(schema)) return;

            using (var connection = GetConnection())

            {

                using (var command = new OracleCommand("alter session set current_schema=" + schema))

                {

                    connection.Open();

                    command.Connection = connection;

                    command.ExecuteNonQuery();

                }

            }

        }

SELECT  TimeGenerated, SourceName, ComputerName, Message FROM C:\Downloads\May09-ErrorLog\AppLog\*.evt
WHERE TimeGenerated BETWEEN timestamp(’04/04/2009′, ‘dd/MM/yyyy’) and timestamp(’06/04/2009′, ‘dd/MM/yyyy’)
ORDER BY TimeGenerated desc

Okay so backed up the data and when I try to format as FAT32 there is no such option on the Explorer ‘Format’ dialog. It’s either NTFS or exFAT, couldn’t figure out if the 360 supported exFAT (should have tried) so went about trying to format from the command line. Which does have a switch for FAT32.

Unfortunately format.exe complains that the partition is too big. What I should not have done was to try a quick format.

Instead I went about deleting the partition as mentioned by several sites. There’s a good one built into Windows (Disk Management) that you can get through from ‘Computer Management’. So right-clicked on the external disc and did a ‘Delete Volume’. And then right-clicked and created a new volume. [NOTE: I think the whole delete and create a new volume can be skipped if you already have the partition in NTFS).

Next tried the format.exe again. Still fails complaining that the disc is too big. At whim tried formatting without the /Q (quick format) option. Worked fine.

Here’s how you would go about it (replace Q: with the drive letter of your portable disc).

C:\>format Q: /FS:FAT32

Win7 (or at least the build I have) by default does not auto expand the tree view when you navigate between folders.

The result being you don’t see the usually tree hierarchy on the left pane. Which makes it quite painful if you want to go up a few levels or see the other parent folders.

Luckily there is a new Folder Option called Navigation Pane to switch them back on again. You need to press Alt + T or Organize –> Folder Search Options in Windows Explorer to get to the dialog.

Switch both of them on and viola I get my beloved tree view back.

PS- Most of my UW colleagues use other explorers and didn’t have to feel this pain.

System.ServiceModel.Security.MessageSecurityException occurred Message="The HTTP request is unauthorized with client authentication scheme ‘Negotiate’. The authentication header received from the server was ‘Negotiate

As described in this bug report Microsoft classifies this as a known issue, with the bug being resolved as ‘By Design’.

Your fix is to add an identity element to the WCF endpoint like this.

<identity>
    <userPrincipalName value="WcfServiceAccount@domain" />
</identity>

But the problem with CCF is that the url for some of the endpoints are read through code from a database and set through the proxy class. Now when you do this the identity from the config file does not flow through resulting in the same exception you see above.

One option is to uninstall the service pack on the client. This is not as easy as it seems because the the 3.5 service pack also updates assemblies in the 2.0 and 3.0 frameworks to their SP2 levels.

To get back to pre 3.5 SP1 you need to uninstall all the frameworks and re-install them again avoiding the 3.5 SP1. The exact steps to do this is outlined here by Microsoft engineer, Aaron Stebner.

But what if you don’t have the luxury of walking all your end-users through the uninstall? A suggested fix from Microsoft (targeting CCF) is as follows:

1. Set up a cNAME in DNS for the servername you are using in database urls.
2. Use setspn -a HOST/CNAME domain\apppooluser
3. Change all the database urls to this CNAME
4. Do an iisreset
5. Test

For example if the database urls are http://ccfserver/…..

1. Create a  CNAME CCFALIAS in DNS
2. setspn -a HOST/CCFALIAS ccf\aspuser
3. Change all database urls to ccfalias
4. iisreset
5. Test if you reach /urls with this alias from web servers and from clients

Be careful not to set HOST/CCFSERVER spn for aspuser. Note we are setting HOST/CCFALIAS spn which is CNAME for ccfserver in DNS. If by mistake you set host/ccfserver it can wreak havoc  for Kerberos.