Search results for 'app:weblogs' matching tag 'DevCenter'

Windows Virtual PC now on MSDN

bill — Thu, 08 Oct 2009 05:00:00 GMT

If you’ve got Windows 7 installed, the Windows Virtual PC for Windows 7 is now on MSDN subscriber downloads !!!

I had the Release Candidate (RC) installed, so had to uninstall that first and reboot before installing the RTM release. All worked perfectly, and my VPC’s from the RC also are working fine :)

If you need to uninstall the RC you’ll find it listed under the “Programs and Features” window from Control Panel. Click on “View installed updates” top left of window, and you’ll find it listed under “Microsoft Windows”

Windows crash recovery

bill — Thu, 24 Sep 2009 05:00:00 GMT

Last night I accidentally pulled out the wrong power plugs, crashing my computer. For some reason this meant it wouldn’t start properly. I don’t quite get why that would mean it wouldn’t start as the hard disc didn’t fail, but none the less it wouldn’t : the computer would seemingly just hang and the keyboard was no longer responsive and its lights went out. The good news is that start-up offered a recovery, and that recovery fixed it and life is good again. The thing to be aware of though is the recovery boot seemed to be hung for a long long time ; I’m talking like 20 minutes or half an hour.

If this happens to you, just be patient: it worked for me :)

Updates on the Snippet Editor

bill — Thu, 03 Sep 2009 05:00:00 GMT

First the good news :

The February release of the Snippet Editor has now had 10,000 downloads !

Now for bug fix news:

There were a couple of issues with the paths per language. A problem with Express Editions of Visual Studio occurred due to partial entries in the registry I didn’t for-see. Initial design and testing was done with full versions of Visual Studio, but I want to ensure that it does work with the express versions, that’s why the tool is standalone not an add-in. So the good news is I have fixed those bugs (I think).

If you want those fixes you can use the original source from Feb and just download the updated products.vb file. I’ll probably look at rolling this up into a new release in the not to distant future.

Enjoy :)

WF4&WCF and message correlation

Maurice — Wed, 02 Sep 2009 05:00:00 GMT

In the previous blog posts, here, here and here, I demonstrated how to use WCF from WF4. This same some more about sending multiple messages to the same workflow, AKA Workflow Correlation.

One of the ugly parts of Windows Workflow Foundation 3 was the message correlation part when you used WCF to send multiple messages to the same workflow.

When using WF3 you where forced to use one of the context bindings like BasicHttpContextBinding or WSHttpContextBinding. Not only that but you also had to retrieve and set the correlation context using the IContextManager and set it to some arcane guid. This guid was the workflow instance ID but having to use that on the client means the client had to be very aware of the server technology used, something that goes against the principals of WCF. Using something in the message itself as to route the message to the correct workflow was just not possible with the build-in activities.

Fortunately the WF4 story is much better. No longer do we need to use the “context” bindings but the standard WCF bindings will do just fine. And the client doesn’t have to work with the workflow instance id but can pass some more logical data, like an invoice number, that will be mapped to the correct workflow. Much better!

To demonstrate this we first need to expand the workflow so it can receive multiple messages for the same workflow. The input for both Receive activities will still be the same person class from the previous example and we will use the persons ID to route the messages.

The new workflow definition looks like this:

private static WorkflowElement CreateWorkflow()

    var result = new Sequence();

    var input = new Variable<Person>();

    result.Variables.Add(input);

    XNamespace ns = "http://tempuri.org";

    var handle1 = new Variable<CorrelationHandle>();

    result.Variables.Add(handle1);

    var handle2 = new Variable<CorrelationHandle>();

    result.Variables.Add(handle2);

    var receive1 = new Receive()

        OperationName = "Operation1",

        ServiceContractName = ns + "MyService",

        Value = new OutArgument<Person>(input),

        AdditionalCorrelations = {

           {"ChannelBasedCorrelation", new InArgument<CorrelationHandle>(handle1)}

},

        CorrelationQuery = CreateCorrelationQuery(),

        CanCreateInstance = true

};

    result.Activities.Add(receive1);

    var write1 = new WriteLine()

        Text = new InArgument<string>(env => string.Format("\tThe workflow was called with '{0}'.", input.Get(env)))

};

    result.Activities.Add(write1);

    var reply1 = new SendReply()

        Request = receive1,

        Value = new InArgument<string>("The result")

};

    result.Activities.Add(reply1);

    var receive2 = new Receive()

        OperationName = "Operation2",

        ServiceContractName = ns + "MyService",

        Value = new OutArgument<Person>(input),

        AdditionalCorrelations = {

           {"ChannelBasedCorrelation", new InArgument<CorrelationHandle>(handle2)}

},

        CorrelationQuery = CreateCorrelationQuery()

};

    result.Activities.Add(receive2);

    var write2 = new WriteLine()

        Text = new InArgument<string>(env => string.Format("\tThe workflow was called again with '{0}'.", input.Get(env)))

};

    result.Activities.Add(write2);

    var reply2 = new SendReply()

        Request = receive2,

        Value = new InArgument<string>("The second result")

};

    result.Activities.Add(reply2);

    return result;

This is very similar to the previous workflow except we have two Receive activities and only the first is configured to allow the message to create a new instance.

The trick in getting the second message routed to the same workflow is by setting the CorrelationQuery on the two Receive activities. This is done in the CreateCorrelationQuery() function as follows:

private static CorrelationQuery CreateCorrelationQuery()

    var result = new CorrelationQuery();

    var xpath = new XPathMessageQuery()

        Namespaces = new XmlNamespaceManager(new NameTable()),

        Expression = "//sample:Person/sample:Id"

};

    xpath.Namespaces.AddNamespace("sample", "urn:WF4Sample:person");

    var messageQuerySet = new MessageQuerySet()

        Name = "RequestCorrelation"

};

    messageQuerySet.Add("PersonId", xpath);

    result.Select = messageQuerySet;

    return result;

The important part here is that the MessageQuerySet key value and the related Expression XPath must produce the same result for both request. Something that is easy here as I am sending in the same person object twice.

So the regular client has hardly any changes. All that is needed is the addition of the second operation to the ServiceContract like this:

[ServiceContract]

interface MyService

    [OperationContract]

    Operation1Response Operation1(Person request);

    [OperationContract]

    Operation1Response Operation2(Person request);

And calling the second operation like this.

static void Main(string[] args)

    var binding = new BasicHttpBinding();

    var endpoint = new EndpointAddress("http://localhost:8090/Sequence1/Operation1");

    var factory = new ChannelFactory<MyService>(binding, endpoint);

    var proxy = factory.CreateChannel();

    var request = new Person()

        Id = 23,

        FirstName = "Joe",

        LastName = "Regular",

        BirthDate = new DateTime(1975, 7, 1)

};

    var result = proxy.Operation1(request);

    Console.WriteLine(result.Value);

    //request.Id = 99;

    request.FirstName = "Maurice";

    request.LastName = "Chevalier";

    request.BirthDate = new DateTime(1888, 9, 12);

    result = proxy.Operation2(request);

    Console.WriteLine(result.Value);

    Console.WriteLine("Regular client is done.");

    Console.ReadLine();

Note that I cam completely free to change the person object as long as I use the same Id. Should I change the Id the WorkflowServiceHost would try and find an existing workflow with the changed person Id, fail and throw a FaultException with message “The requested operation could not complete because instance key '4d7e998a-4cff-4743-3dd4-2afd5578383c' could not be found.”. Not quite sure where the Guid comes from but there is no workflow with that instanceId.

The good thing here is that the client doesn’t need to be aware of the workflow implementation on the server and the server can use “regular” message data to determine the correct workflow to send the message to.

The Workflow client has about the same change. In this case the Send activity is duplicated but other that that there is very little change and certainly no code that makes the client workflow aware of the service workflow.

private static WorkflowElement CreateWorkflow()

    var result = new Sequence();

    XNamespace ns = "http://tempuri.org";

    var endpoint = new Endpoint()

        Uri = new Uri("http://localhost:8090/Sequence1/Operation1"),

        Binding = new BasicHttpBinding()

};

    var response = new Variable<string>();

    result.Variables.Add(response);

    var handle = new Variable<CorrelationHandle>();

    result.Variables.Add(handle);

    var person = new Person()

        Id = 7,

        FirstName = "Maurice",

        LastName = "de Beijer",

        BirthDate = new DateTime(1962, 8, 24)

};

    var request = new Send()

        OperationName = "Operation1",

        Endpoint = endpoint,

        AdditionalCorrelations =

           {"ChannelBasedCorrelation", new InArgument<CorrelationHandle>(handle)}

},

        ServiceContractName = ns + "MyService",

        Value = new InArgument<Person>(person)

};

    result.Activities.Add(request);

    var reply = new ReceiveReply()

        Request = request,

        Value = new OutArgument<string>(response)

};

    result.Activities.Add(reply);

    var write = new WriteLine()

        Text = new InArgument<string>(response)

};

    result.Activities.Add(write);

    var delay = new Delay()

        Duration = TimeSpan.FromSeconds(5)

};

    result.Activities.Add(delay);

    var request2 = new Send()

        OperationName = "Operation2",

        Endpoint = endpoint,

        AdditionalCorrelations =

           {"ChannelBasedCorrelation", new InArgument<CorrelationHandle>(handle)}

},

        ServiceContractName = ns + "MyService",

        Value = new InArgument<Person>(person)

};

    result.Activities.Add(request2);

    var reply2 = new ReceiveReply()

        Request = request2,

        Value = new OutArgument<string>(response)

};

    result.Activities.Add(reply2);

    var write2 = new WriteLine()

        Text = new InArgument<string>(response)

};

    result.Activities.Add(write2);

    return result;

Conclusion.

The WF3/WCF marriage in Wf3.5 left quite a bit to be desired and fortunately live has become a lot simpler with WF4.

Enjoy!

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

Sending your own objects to a WF4 workflow

Maurice — Thu, 20 Aug 2009 05:00:00 GMT

In the previous two blog posts (here and here) I showed how to create and expose a Windows Workflow Foundation 4 workflow via WCF and have both a workflow and a regular C# client work with it. But the parameter and return value where real simple with just a string each. So how about passing some more complex data.

To show how to do so I will replace the singe string with a person object. Admittedly not the most complex person with only an id, first and last name and their birth date but enough to demonstrate the principal.

The main of the service, which uses a WorkflowServiceHost, stays exactly the same so see the first blog post for that part. The CreateWorkflow() function will change now reflecting the fact that the service will no longer expect a string but a person object.

private static WorkflowElement CreateWorkflow()

    var result = new Sequence();

    var input = new Variable<Person>();

    result.Variables.Add(input);

    XNamespace ns = "http://tempuri.org";

    var handle = new Variable<CorrelationHandle>();

    result.Variables.Add(handle);

    var receive = new Receive()

        OperationName = "Operation1",

        ServiceContractName = ns + "MyService",

        Value = new OutArgument<Person>(input),

        AdditionalCorrelations = {

           {"ChannelBasedCorrelation", new InArgument<CorrelationHandle>(handle)}

},

        CanCreateInstance = true

};

    result.Activities.Add(receive);

    var write = new WriteLine()

        Text = new InArgument<string>(env => string.Format("\tThe workflow was called with '{0}'.", input.Get(env)))

};

    result.Activities.Add(write);

    var reply = new SendReply()

        Request = receive,

        Value = new InArgument<string>("The result")

};

    result.Activities.Add(reply);

    return result;

Not a big change really as we only have to change the input variable from Variable<string> to Variable<Person> and do the same with the Value property of the Receive activity which goes from new OutArgument<string>(input) to new OutArgument<Person>(input).

That leaves the Person class and this is just straightforward WCF work by turning the basic class into a data contract.

[DataContract(Namespace = "urn:WF4Sample:person")]

public class Person

    [DataMember]

    public int Id { get; set; }

    [DataMember]

    public string FirstName { get; set; }

    [DataMember]

    public string LastName { get; set; }

    [DataMember]

    public DateTime BirthDate { get; set; }

    public override string ToString()

        return string.Format("{0} {1} was born on {2} (ID: {3})", FirstName, LastName, BirthDate, Id);

Again no big deal

So with the service done we need to make the same changes to the two client applications. First the workflow client using the Send activity.

The Person class is exactly the same as on the server so just copy the code as is. Again the main in the workflow client doesn’t change, see the first blog post for that part. The part that does change a little is the CreateWorkflow() function so it creates and sends a Person instead of a string. The code goes as follows:

private static WorkflowElement CreateWorkflow()

    var result = new Sequence();

    XNamespace ns = "http://tempuri.org";

    var endpoint = new Endpoint()

        Uri = new Uri("http://localhost:8090/Sequence1/Operation1"),

        Binding = new BasicHttpBinding()

};

    var response = new Variable<string>();

    result.Variables.Add(response);

    var handle = new Variable<CorrelationHandle>();

    result.Variables.Add(handle);

    var person = new Person()

        Id = 7,

        FirstName = "Maurice",

        LastName = "de Beijer",

        BirthDate = new DateTime(1962, 8, 24)

};

    var request = new Send()

        OperationName = "Operation1",

        Endpoint = endpoint,

        AdditionalCorrelations =

           {"ChannelBasedCorrelation", new InArgument<CorrelationHandle>(handle)}

},

        ServiceContractName = ns + "MyService",

        Value = new InArgument<Person>(person)

};

    result.Activities.Add(request);

    var reply = new ReceiveReply()

        Request = request,

        Value = new OutArgument<string>(response)

};

    result.Activities.Add(reply);

    var write = new WriteLine()

        Text = new InArgument<string>(response)

};

    result.Activities.Add(write);

    return result;

Again a very minor change.

So how about the C# console client from the second blog post?

The service contract changes a little and is now:

[ServiceContract]

interface MyService

    [OperationContract]

    Operation1Response Operation1(Person request);

The person class is very different from the service though and looks like this:

[MessageContract(WrapperNamespace = "urn:WF4Sample:person")]

internal class Person

    [MessageBodyMember(Namespace = "urn:WF4Sample:person")]

    public int Id { get; set; }

    [MessageBodyMember(Namespace = "urn:WF4Sample:person")]

    public string FirstName { get; set; }

    [MessageBodyMember(Namespace = "urn:WF4Sample:person")]

    public string LastName { get; set; }

    [MessageBodyMember(Namespace = "urn:WF4Sample:person")]

    public DateTime BirthDate { get; set; }

But besides the difference from using a message contract as opposed to a data contract this isn’t a big deal.

The main program changes a bit but not a whole lot. Again the only changes are due to the fact we are passing in a Person instead of a string.

static void Main(string[] args)

    var binding = new BasicHttpBinding();

    var endpoint = new EndpointAddress("http://localhost:8090/Sequence1/Operation1");

    var factory = new ChannelFactory<MyService>(binding, endpoint);

    var proxy = factory.CreateChannel();

    var request = new Person()

        Id = 23,

        FirstName = "Joe",

        LastName = "Regular",

        BirthDate = new DateTime(1975, 7, 1)

};

    var result = proxy.Operation1(request);

    Console.WriteLine(result.Value);

    Console.WriteLine("Regular client is done.");

    Console.ReadLine();

All together not bad.

But so far we have only used a very simple workflow with a single message send to it. Suppose you want to send multiple messages to the same workflow? Well in that case we need to use message correlation as we will see next time.

Enjoy!

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

Combined DevelopMentor instructors blog feed.

Maurice — Wed, 19 Aug 2009 05:00:00 GMT

Michael Kennedy, one of the co instructors from DevelopMentor, has created a combined feed from all the blogs of the various DevelopMentor. An awesome group of people with a lot of knowledge to share. Highly recommended in you RSS reader.

http://feeds.feedburner.com/DevelopmentorInstructors

If you want to check out a list of the individual blog feeds look here.

Enjoy!

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

Screen-cast recording tools

bill — Mon, 17 Aug 2009 05:00:00 GMT

Recently I got this email from Ted:

Hi Bill!

Love the snippet tool, it's great!

I'm curious, what tool did you use to produce the screencast for the tool? The quality is awesome!

Thanks a lot!

Kind regards,

Ted

The answer to that is I used Camtasia Studio 5. It’s really easy to use and lots of options on output formats. And it will even produce the basic html file for you with the embedded video etc.

Note: I really like Camtasia. I do also get it for free from the nice folks at TechSmith as they value the contribution MVPs make to the community, and that makes it even easier to like :)

An alternative worth looking at is Expression Encoder 3 Screen Capture which comes with Microsoft Expression 3. I’ve only given it a quick test drive and it seemed pretty good. Picking formats was a little daunting, but I got it to produce some good quality wmv files that were really good for the bandwidth (small file size). I haven’t driven it enough to find how to produce web files that embed the video; my guess is it would be more silverlight orientated. Still if you have a MSDN subscription that includes expression, it’s definitely worth a look at.

Using ASP.NET MVC

Maurice — Thu, 13 Aug 2009 05:00:00 GMT

Recently I started using ASP.NET MVC for a real project. SO far I had been reluctant to use ASP.NET MVC as it meant giving up on the post back model that so many of the available ASP.NET controls depend on. Yet a lot of people I know and respect where saying good things about ASP.NET MVC so I decided to try it out on a small but real project.

Well the project isn’t finished yet but I am a convert

Using ASP.NET MVC is much nicer that I expected it to be. Sure the post back model, and with it a lot of controls, are gone but I started doing more client side stuff using jQuery and the many plug-ins available. And even where not doing a lot of client side work ASP.NET MVC makes live quite easy.

The main difference is that ASP.NET MVC lends itself very well to test driven development. Now I not a pure TDD zealot but covering a lot of the code with unit test, regardless if you create the test first or later, is pretty much a requirement of a good software project. And ASP.NET MVC lend itself much better to unit testing than ASP.NET web forms.

ASP.NET MVC will not be the thing for everyone. If you are heavy into designers and drag-drop development web forms will be a better match for you. But if you are like me and like working with code ASP.NET MVC is a joy to work with.

The book I keep by my side is Steven Sanderson’s Pro ASP.NET MVC Framework. It has been very valuable, both on giving me a behind the scenes insight and solving some practical issues I ran into.

Error Logging Modules and Handlers for ASP.NET (MVC)

Maurice — Thu, 13 Aug 2009 05:00:00 GMT

I am working on a new ASP.NET MVC app and like so many other applications out there I need to log any errors should they occur. recently I heard about ELMAH Error Logging Modules and Handlers for ASP.NET through this blog post of Scott Hanselman. So as using en existing and proven solution is always better that reinventing the wheel I decided to try ELMAH and see how easy it is to get started.

Well I can only say I am positively amazed at how easy it is.

Starting from scratch it took me less that 2 hours to download and integrate it into my current ASP.NET MVC application and log all errors to SQL Server. That is including security so not everyone can check the error log.

There are lots of additional capabilities I haven’t looked at yet like setting up an RSS feed, emailing or even tweeting errors messages. But judging from the experience so far that should prove easy enough.

My only regret is that I didn’t check it out before.

Checkout the project run by Atif Aziz here.

Enjoy!

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

Expression 3 is on MSDN

bill — Mon, 27 Jul 2009 05:00:00 GMT

With all the focus on Windows 7 RTM announcements, the availability of Expression 3 on the MSDN site last Thursday may have sneaked under folks radars. For MSND subscribers, grab your copy of Expression 3.