Retrieving objects in C#

Receive barcode 39 in C# Retrieving objects

Figure 2 shows the results of running the code. The usefulness of TVPs becomes apparent only with more real-world examples that are called from ADO.NET client applications, so we ll explore that next.

PS (4) > $a[0] = "0xabc"

Figure 3 16. Resetting sync history in iTunes (Edit > Preferences > Devices tab)

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After opening the database, you ll want to make some requests in SQL. These range from creating the initial tables to data access operations. This is considerably more involved and takes up the majority of the lines of code for this class. The simplest statement has no parameters: Select * from GroceryItem. You can create a function in ISDatabase.m to handle these statements:

Imagine you have a class called Beer that implements the basic attributes and behavior of beer. The properties held by this class apply equally to all types of beer. Rather than re-implement these properties for each kind of beer, you make the Beer class a base (or parent) class and derive other beers from it, which absorb the basic attributes and behavior of the parent class. For each new beer, you implement only attributes and behavior specific to that type of beer, and reuse the basic properties from the parent Beer class. In OOP, this process is called inheritance. Inheritance enables you to use the attributes (data) and behavior (methods) of other classes as a starting point for creating specialized versions of a class. In doing so, you create hierarchies of objects, each a specialization of its parent(s). Many OO languages support both single inheritance, where you inherit from a single class, and multiple inheritance, where you inherit from multiple classes. However, Objective-C does not support multiple inheritance. You can also extend class properties through categories. Categories enable you to add new methods to a class without using inheritance. For some applications, categories offer advantages over inheritance and are a good way to enhance an existing class. You can specify a category in an interface and implementation file. The syntax for categories is as follows:

Click Yes to continue. Once authorization is complete, you will see a screen showing how many of your five total authorizations have been used up (see Figure 26 25). To learn more about authorizing or deauthorizing computers, see the Authorize and Deauthorize Computers section later in this chapter.

Let s see how to use some of these members to display the list of photographs contained in an album. The following steps create a new MyAlbumEditor application. We will use this application throughout this chapter to demonstrate how various controls are used. Here, we will open an album and display its contents in a ListBox using some of the members inherited from ListControl.

PS (6) > trace-command -opt all typeconversion -pshost ` >> -listen timestamp ` >> { [xml] '<h>Hi</h>' } >> DEBUG: TypeConversion Information: 0 : Converting "xml" to "System.Type". DEBUG: Timestamp=5536598202692

void SquareIt( int number, int *squarePtr );