Let’s now look at another advantage of using a DataTable. A lot of developers today are used to using LINQ. After loading data into a DataTable you can iterate using a foreach statement, or you can use LINQ to create a collection of entity objects. The DataRow class has an extension method called Field that allows you to check the data and return either a null or the real data value. Of course this means you have to use Nullable types for your properties in your class. Below is the definition of a Product class that uses all Nullable types.

As discussed in my last two blog posts you have a variety of ways to create collections of Entity classes. Using a DataSet or DataTable is a little slower than using a DataReader, but in most cases the difference is in milliseconds so in a real world app this difference would not be a killer. For instance, in my sample data I was loading 6,261 records from the Product table discussed in the last blog post and it took 45 milliseconds on average to load those records into an entity collection using a DataTable. It took only 30 milliseconds on average to load the same entity collection using a DataReader. The rendering of that data would probably take longer than that, so you can choose which one you wish to use.

As discussed in the last blog post, it is a best practice to build entity classes. In the last post we filled a DataTable with Category data and then iterated over that DataTable to create a collection of Entity classes. In this blog post we will use a SqlDataReader to fill the Entity classes.

What is an Entity Class

One of the navigation mechanisms used in Windows 8 and Windows Phone is a Tile. A tile is a large rectangle that can have words and pictures that a user can click on. You can build your own version of a Tile in your WPF or Silverlight applications using a User Control. With just a little bit of XAML and a little bit of code-behind you can create a navigation system like that shown in Figure 1.

Some of our customers are asking us to give them a Windows 8 look and feel for their applications. This includes things like buttons, tiles, application bars, and other features. In this blog post I will describe how to create a button that looks similar to those you will find in a Windows 8 application bar.

Instead of a normal button with words, sometimes you want a button that is just graphical. Yes, you can put an Image control in the Content of a normal Button control, but you still have the button outline, and trying to change the style can be rather difficult. Instead I like creating a user control that simulates a button, but just accepts an image. Figure 1 shows an example of three of these custom user controls to represent minimize, maximize and close buttons for a borderless window. Notice the highlighted image button has a gray rectangle around it. You will learn how to highlight using the VisualStateManager in this blog post.

In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details.