I Can't Believe That Worked

Silverlight Bing Maps Control and Drag & Drop

David Justice — Sat, 17 Apr 2010 19:57:00 GMT

I was recently asked to build up a Silverlight tool to show a file full of addresses on a map. I decided to use the Silverlight bing maps control and I must say I was not disappointed with it's functionality. It ended up being extremely simple. The tools used to create this were VS2010, Silverlight 4, Bing maps Silverlight control, and the Bing maps web services.

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XAML Default Button

David Justice — Wed, 02 Sep 2009 11:20:00 GMT

I was working with a client that wanted to have a default button clicked when an enter key is pressed in a textbox (password box to be more specific) within a Silverlight or WPF application. I didn't think much of it. I'll just listen to the event, bind to the button, and click the button on the enter key event. The listening and binding portion is not very tough with an attached property and a little Silverlight 3 element to element binding love. The tricky part came in when I wanted to cause the button click event to be raised. I ended up having to take a page from Josh Smith http://joshsmithonwpf.wordpress.com/2007/03/09/how-to-programmatically-click-a-button/. Thank you, Josh! This may not be the best way to do this, but it works for me.

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Genetic Algorithm -- Add Ur Own Func :)

David Justice — Mon, 29 Jun 2009 05:34:00 GMT

Hi again,

I was a little bored this weekend and needed to add in some GA functionality to a side project. I felt like it would be best to create a simple executer to deal with the iterative behavior of a genetic algorithm. The executer take in funcs provided by the consumer and executes based on a simple iterative model. Below is what I came up with. Cheers!

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.Net 4.0 Reflection vs. Dynamics vs. Property Setting With Times

David Justice — Fri, 26 Jun 2009 13:26:00 GMT

Today I found my self hanging out after a sprint review with my partner in crime Kevin Rohling. TFS was down (not tfs's fault, but some other freak accident...) and I hadn't installed VS 2010 yet, so it seemed like the perfect time to do such things. I got everything up and running, and Kevin and I got into a discussion about Dynamics & performance. We made a quick lunch bet on which is faster, reflection or dynamics for simply setting a property. I figured reflection would be quicker, while Kevin thought dynamics would be faster. Well, I owe him lunch now. The code is below.

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Silverlight Facebook Client Side API v0.001

David Justice — Thu, 22 Jan 2009 05:30:00 GMT

In a past post (Facebook Connect Post) I showed everyone how to set up an application in Facebook and how to use Facebook Connect with Silverlight to create a simple login screen. That was a trivial proof of concept to show how one might implement such things on their Silverlight App. This post will build on the previous post, and introduce a very alpha version of a Silverlight client side api I have been working on for a little bit.

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Azure 1/10 + Facebook Connect 1/2 + Silverlight 2/5 = Fun

David Justice — Thu, 04 Dec 2008 16:46:00 GMT

Hello all! First off, I want to say this post does not reflect the way I think authentication should be handled. I don't necessarily agree with the route Facebook has decided to go with Connect, but that is a debate I don't really wish to be a part of right now. I would like to concentrate on the superlatives about Facebook Connect and the possibilities this opens up to developers. If you wish to discuss the positives and negatives of the Facebook Connect strategy, please be my guest to comment till your angelic heart is content.

In this post, I'm going to set up an Azure cloud service project with a single web role that hosts a Silverlight 2 page, which utilizes Facebook Connect. I will not go into other portions of the Facebook API during this post, but I will extend it in a later post. Basically this is 1/10 an excersize in creating a cloud service, 1/2 using Facebook connect, and about 2/5 interactions between JavaScript and Silverlight. Ok, let's get started.

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Silverlight 2 XAML Binding and Custom / Core Dependency Properties

David Justice — Sun, 23 Nov 2008 09:14:00 GMT

Lately, I have been working in Silverlight 2 quite a bit. I have been infused with inspiration from the Chicago PhizzPop Design Challenge . I'm waiting for the pictures and vids from a couple people to be served. I will be linking them into the blog...(read more)

Silver Lining for Windows Azure -- Silverlight 2 Sample Hosted in Azure

David Justice — Sat, 08 Nov 2008 07:00:00 GMT

OK, so I'm starting to sound repetitive about my excitement around Windows Azure, but I really think it will help developers create new products with an all time low cost to enter their specific market. Not only will it cost less to enter into their market, I think it will help them scale their service offerings as their business grows. We all want our businesses to grow, but many of the initial development choices one makes when driving to release a product do not always make sense when your customer base grows in a few orders of magnitude.

I'm also stoked about the Silverlight Toolkit released 10.29.2008 (haven't used stoked in a while - I wonder if I can bring it back...). These controls make developing for Silverlight a real joy. I was skeptical about the Silverlight 1 release, as well as the initial release of WPF (which is like forever ago), not because of the architecture or technology, but because of the lack of controls. In the case of WPF, many of my fellow developers refused to move from Windows Forms, because of the rich tool sets they already had. I think MS heard the call and has worked to remedy the situation.

I melded an Azure Web Role project and the Silverlight Toolkit sample to give you guys a quick download, so you can play with them together. I hope you like it, and I hope it helps you explore some of the new technology. I call it SilverLining.

You'll need the Azure SDK, and Silverlight tools.

Twitter: @DavidJustice

Unique Identifier Flat File Import with SSIS

David Justice — Fri, 07 Nov 2008 07:44:00 GMT

This morning I found myself wrestling with SSIS to convert a string from a flat file to a unique identifier via a Data Flow inside of an SSIS package. I figured this would be a rather trivial case (the midget was kicking my ass!). I use guids all over for application development and for database keys. They are very useful, and very dependable. Here is a line from my flat file:

61898d4c-3a1b-4736-9a36-eb90a23322e0|:|10/13/2008 11:59:58 PM|:|74afebfe-9523-4977-b5f6-5154b6c91211

Anyone see anything wrong with this? I didn't see anything wrong, outside of the silly |:| delimiter (I don't want to get started on that <rant/> <--- rant with no content!).

So moving forward, I created a Flat File Source, pointed to the file, had it guess the appropriate type for import (it selected a 36 character dt_str - fine with me), and then went into the advanced edit section and changed the output for the column to be a unique identifier. I would expect the conversation to take place in the middle somewhere, and if the powers that be smile kindly upon me, all should work out well. Unfortunately, I would get an error about truncating data, "The value could not be converted because of a potential loss of data." I was very confused by this. I tried to push the string input from the flat file data through a Data Converter step and do the conversion there, but that had the same results. Basically from that point on for about an hour, I tried every different way I could think of to convert that guid string into a SQL unique identifier.

Eventually I gave up. The web turned up little help, and I was nearing my wits end. I don't enjoy working on SSIS packages, and this was not helping. Thankfully, I have an in-house SQL ROCKSTAR!! My good friend Chuck (a SQL MVP) has helped me though all sorts of SQL issues in the past. I asked him about this issue, and although he wasn't completely sure, he thought the error might be because I didn't wrap the guid strings in braces. <rant> I thought he was absolutely insane! Why the heck would SSIS expect those guids to be in braces!? Why couldn't it cast them as unique identifiers? I can say ‘61898d4c-3a1b-4736-9a36-eb90a23322e0' as uniqueidentifier, and the T-SQL world doesn't come to a grinding halt!! </rant>

The new input looks like this:

{61898d4c-3a1b-4736-9a36-eb90a23322e0}|:|10/13/2008 11:59:58 PM|:|{74afebfe-9523-4977-b5f6-5154b6c91211}

I went through the steps above, and tested the solution. That's it! It works like a champ now. Thx u Chuck!!

Twitter: @DavidJustice

MetaTable Expression Builder for Fetching Any Object Via Collection of Primary Keys

David Justice — Tue, 04 Nov 2008 07:53:00 GMT

Basically, I wanted to build a method that gets an object from a data context whatever the primary key may look like, and whatever type that object may be.  I wrote this code a little while ago when I was exploring the DynamicData libs.  I was checking out some of the code in the libs, and noticed a very slick way one of devs was building expressions to grab back a data item based on a single key ID.  I thought the idea of building up the expression completely ROCKED, but I wanted to expand it out to include composite primary keys.  Below is my implementation of the composite primary key object fetcher.  Hopefully, it will make your life a little easier.
 
(Needed to grab the MetaModel class)
 
using System.Web.DynamicData;
 
(Create a new MetaModel for your Context or Contexts -- make sure they are only registered once!!  This can be an issue if you put this code in a static constructor, and you happen to have a generic class.  That would cause the code to get executed each time you specify a new generic argument for type construction (sry, I digress))

 
Model = new MetaModel();
Model.RegisterContext(typeof([Your Context Type]));
 
(Get your meta table based on the type from your registered context -- need the metadata about the table to figure out the keys)

protected static MetaTable GetMetaTable<T>()
{
    return dataModelMetaModel.GetTable(typeof (T));
}

(This is where the heavy lifting occurs.  I commented what is going on.  There is not much more to say.  Enjoy!)
 

private static T FetchObject<T>(MetaTable metatable, IDictionary<string, object> pks)
    where T : class
{
    IQueryable query = metatable.GetQuery();
 
    //build linq expression tree for where clause
    ParameterExpression entityparam = Expression.Parameter(metatable.EntityType, "e");
    List<Expression> internalExpressons = new List<Expression>();
    Expression equalexpression;
    foreach (MetaColumn member in metatable.PrimaryKeyColumns)
    {
        //convert primary key to proper type
        PropertyInfo columnpropertyinfo = member.EntityTypeProperty;
        MemberExpression columnexpresson = Expression.MakeMemberAccess(entityparam, columnpropertyinfo);
        internalExpressons.Add(Expression.Equal(columnexpresson, Expression.Constant(pks[member.Name])));
    }
 
    // build up the primary key expressions
    if (internalExpressons.Count > 1)
    {
        equalexpression = Expression.And(internalExpressons[0], internalExpressons[1]);
        for (int i = 2; i < internalExpressons.Count; i++)
        {
            equalexpression = Expression.And(equalexpression, internalExpressons);
        }
    }
    else
    {
        equalexpression = internalExpressons[0];
    }
 
    // Create the where clause
    LambdaExpression wherelambda = Expression.Lambda(equalexpression, entityparam);
    MethodCallExpression wherecall = Expression.Call(typeof (Queryable), "Where", new[] {metatable.EntityType},
                                                     query.Expression, wherelambda);
    query = query.Provider.CreateQuery(wherecall);
 
    // Call FirstOrDefault to make sure the connection is closed when finished
    // saw some connections staying open when just grabbing the first object.
    return query.Cast<T>().FirstOrDefault();
}
 
Twitter: @DavidJustice

Windows Azure and _NOT_ SQLExpress

David Justice — Sun, 02 Nov 2008 10:37:00 GMT

I've been very excited recently by the release of Windows Azure, and rest of the Microsoft suite of cloud based services. I downloaded all of the sdk's, signed up for all the invitation tokens I could, and began writing code. The Visual Studio templates for Windows Azure projects makes getting your first Azure project up and running super simple. I did run into one issues with the project templates setting up my first project.

Basically, the DevelopmentStorage.exe.config for windows Azure expects you to have SQLExpress installed on your machine. I know it probably says it in quite a few places in the documentation, but instructions and documentation are for after the first faliure ;). I don't have SQLExpress installed on my machine. I run SQL2008 Dev... Now, it would not be very tough to go out and download SQLExpress, but I don't want to (a bit of laziness is good for all developers, without it your code would never be DRY). So, I just went into the DevelopmentStorage.exe.config, and editted the refs for SQLExpress, and just replaced it with localhost (I have an unnamed instance), and all was well in the world of Azure DB Objects. You should be able to find your DevelopmentStorage.exe.config at C:\Program Files\Windows Azure SDK\v1.0\bin.

I hope you have clear blue skys ahead of you!

UPDATE: I noticed that my development storage was not starting the table service for me. I reflected out the developmentstorage.exe and found that I was not supplying a proper dbName in the configuration file. I doctored up my DevelopmentStorage.exe.config configuration file to look like this:

Twitter: @DavidJustice