What Was I Thinking?

Enabling Sql Server Broker Service Hangs

ChrisD — Sat, 28 Jan 2012 21:53:00 GMT

If your connection hangs while attempting to start sql server broker service, its likely caused by the system trying to gain exclusive access to your database. Some people recommend stopping and restarting the sql server instance. I find that a little heavy-handed, like swatting a fly with a sledge hammer. Instead switch the database into single user mode, enable the broker service, and restore the database to multi-user mode.

1) Set the database to single user mode:

ALTER DATABASE [DBNAME] SET SINGLE_USER WITH ROLLBACK IMMEDIATE

2) Enable Broker Service on the database

ALTER DATABASE [DBNAME] SET ENABLE_BROKER;

3)Restore the database to multi-user mode

ALTER DATABASE [DBNAME] SET MULTI_USER

Of course you’ll need proper permissions, but enabling the service this way prevents interruption to any other databases running on your server.

Also make sure Broker Service is enabled:

SELECT is_broker_enabled FROM sys.databases WHERE name = ‘DBNAME’;It should return 1 if its enabled.

-- Enable Service Broker:
ALTER DATABASE [DBNAME] SET ENABLE_BROKER;

-- Disable Service Broker:
ALTER DATABASE [DBNAME] SET DISABLE_BROKER;

Google’s Public DNS Servers

ChrisD — Wed, 26 Oct 2011 19:48:00 GMT

Tired of ISP DNS service errors? switch to use Google’s. They are FAST and ALWAYS available.

Primary: 8.8.8.8

Secondary: 8.8.4.4

Performing Case-Insensitive joins using EXCEPT operator in LINQ

ChrisD — Wed, 26 Oct 2011 06:20:00 GMT

   1:   var daysOfWeek = new[] { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };

   2:   var workDays = daysOfWeek.Except( new []{ "SUNDAY", "SaTURdaY"}); // Performs a case sensitive search and yields Sunday,Monday - Saturday.

   3:  workDays = daysOfWeek.Except(new[] { "SUNDAY", "SaTURdaY" },StringComparer.OrdinalIgnoreCase); // Performs a case insensitive search and yields Monday-Friday

The except operator takes a comparer that tells it how to evaluate the two lists. Nice one!

How can I include my derived class type name in the serialized JSON?

ChrisD — Fri, 01 Jul 2011 01:35:34 GMT

Sometimes working with the js Serializer is easy, sometimes its not. When I attempt to serialize an object that is derived from a base, the serializer decided whether or not to include the type name.

When its present, the type name is represented by a ___type attribute in the serialized json like this:

{"d":{"__type":"Commerce.Integration.Surfaces.OrderCreationRequest","RepId":0}}

The missing type name is a problem if I intend to ship the object back into a web method that needs to deserialize the object. Without the Type name, serialization will fail and result in a ugly web exception.

The solution, which feels more like a work-around, is to explicitly tell the serializer to ALWAYS generate the type name for each derived type. You make this declaration by adding a [GenerateScriptType())] attribute for each derived type to the top of the web page declaration.

For example, assuming I had 3 derivations of OrderCreationRequest; PersonalOrderCreationRequest, CompanyOrderCreationRequest, InternalOrderCreationRequestion, the code-behind for my web page would be decorated as follows:

    [GenerateScriptType(typeof(PersonalOrderCreationRequest))]
    [GenerateScriptType(typeof(CompanyOrderCreationRequest))]
    [GenerateScriptType(typeof(InternalOrderCreationRequest))]
    public partial class OrderMethods : Page
{
...
}

With the type names generated in the serialized JSON, the serializer can successfully deserialize instances of any of these types passed into a web method.

Hope this helps you as much as it did me.

QuickTip: Determine if Type implements IEnumerable<T>

ChrisD — Thu, 28 Apr 2011 13:26:23 GMT

I was working on a project that required a determination if the type was an IEnumerable collection of some type.

Using a bit of reflection and the handy-dandy GetGenericTypeDefinition method, I arrive at this:

Code Snippet
 public static bool IsIEnumerableOfT(Type type)
      {
          return type.GetInterfaces().Any(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof (IEnumerable<>)) ;
      }
 

Happy Coding!

Reorder Your Accounts in Thunderbird

ChrisD — Wed, 20 Apr 2011 16:57:28 GMT

Ever wanted to re-order your Thunderbird accounts?

You can either modify the prefs.js manually

1. Exit Thunderbird if its running.

2. Locate your prefs.js file (default location is c:\users\[your account]AppData\Thunderbird\Profiles

3. create a backup , just in case.

4. Open the prefs.js in any text editor and look for: user_pref("mail.accountmanager.accounts", "account1,account2,account3,account4…"); line

5. Change the order of the accounts manually

6. Restart Thunderbird

1. Download and install the FolderPane add-on.

2. From Thunderbird, select Tools->Add ons –> Folderpane and reorder the accounts using the “Move Up” and “Move Down” buttons.

3. Close and restart Thunderbird.

The choice is yours.

QuickTip: Selecting Children from a Parent Item in Linq

ChrisD — Tue, 29 Mar 2011 20:47:27 GMT

I’m posting this here because I keep forgetting the syntax, and thought others might benefit as well.

Given :

public class ParentItem

{

IEnumerable<ChildItem> Children

}

Selecting all the childitem instances from an IEnumerable<ParentItem>:

var allChildren = ParentItems.SelectMany(parent=>parent.Children);

Selecting matching childItem instances from an IEnumerable<ParentItem>:

var selectedChildren = ParentItems.SelectMany(parent=>parent.Children).Where(child=><boolean expression for filtering children>)

Words of Wisdom

ChrisD — Sat, 19 Mar 2011 15:59:25 GMT

Culture beats Strategy every time.

How to set x509 Certificate private key access rights for AppPoolIdentity

ChrisD — Tue, 15 Mar 2011 17:09:28 GMT

If your website uses the AppPoolIdentity and requires access to the private key of an x509Certficate, you’ll need to grant the read permissions to the iis application pool.

To grant permissions to the AppPoolIdentity:

Run Certificates.MMC (or Start->run->mmc.exe, Add Certificate Snap-In for LocalMachine)
Select the certificate (Personal node on the certificate tree) , right click and Manage Permissions.
Add a new user to the permissions list.
Enter "IIS AppPool\AppPoolName" on the local machine". Replace "AppPoolName" with the name of your application pool.

Fixing LINQ Error: Sequence contains no elements

ChrisD — Tue, 15 Feb 2011 14:59:05 GMT

I’ve read some posts regarding this error when using the First() or Single() command. They suggest using FirstOrDefault() or SingleorDefault() instead.

But I recently encountered it when using a Sum() command in conjunction with a Where():

Code Snippet
 var effectiveFloor = policies.Where(p => p.PricingStrategy == PricingStrategy.EstablishFloor).Max(p => p.Amount);
 

When the Where() function eliminated all the items in the policies collection, the Sum() command threw the “Sequence contains no elements” exception.

Inserting the DefaultIfEmpty() command between the Where() and Sum(), prevents this error:

Code Snippet
 var effectiveFloor = policies.Where(p => p.PricingStrategy == PricingStrategy.EstablishFloor).DefaultIfEmpty().Max(p => p.Amount);
 

but now throws a Null Reference exception!

The Fix:

Using a combination of DefaultIfEmpty() and a null check in the Sum() command solves this problem entirely:

Code Snippet
 var effectiveFloor = policies.Where(p => p.PricingStrategy == PricingStrategy.EstablishFloor).DefaultIfEmpty().Max(p =>  p==null?0 :p.Amount);
 