barcode generator in asp.net code project Part IV in .NET

Implement Denso QR Bar Code in .NET Part IV

This generates the following output:

(default for the Workstation GC mode)

In addition to the checked and unchecked operators, C# also offers checked and unchecked statements . The statements cause all expressions within a block to be checked or unchecked:

Next, define the constructor for your JavaScript class as a function. In this case, the constructor takes the element parameter. This is meant to represent the DOM element that the control extends. Use this element to initialize the base class of System.UI.Control. This control will set the style of a text box based on the strength of the password. Therefore, it exposes three properties, one for each password strength. Inside the constructor, initialize the private fields used to represent these properties. The following shows an example of the constructor.

orderid ----------10692 10702 10643 10835 10952 11011 custid ----------1 1 1 1 1 1 empid ----------4 4 6 1 1 3 orderdate ----------------------2007-10-03 00:00:00.000 2007-10-13 00:00:00.000 2007-08-25 00:00:00.000 2008-01-15 00:00:00.000 2008-03-16 00:00:00.000 2008-04-09 00:00:00.000

DECLARE @area GEOMETRY; DECLARE @region GEOMETRY; DECLARE @distance FLOAT; SET @distance = .4; SET @area = (SELECT GEOM FROM Polygons WHERE NAME = 'Area1'); SET @region = @area.STBuffer(@distance).STDifference(@area.STBuffer(@distance * -1)); SELECT NAME FROM Points WHERE GEOM.STIntersects(@region)=1;

Refer to the "Unsafe Code" section in 6 for comprehensive coverage of the keywords in Table 4-9.

Class Description Provides a basis for strongly typed collections. CollectionBase ReadOnlyCollectionBase Provides a basis for strongly typed collections that don't permit elements to be modified. Provides a basis for strongly typed collections of key/value pairs. DictionaryBase The most interesting aspect of these classes is that none of the collections detailed in this chapter are derived from them. There is no specific reason why custom collections have to be subclassed from one of these bases, but it is generally good practice to do so.

by these types are designed specifically for use by developers who are producing compilers for the CLR . Application developers don t typically use these types and members . The Framework Class Library (FCL) documentation doesn t explicitly point out which of these types and members are for compiler developers rather than application developers, but if you realize that not all reflection types and their members are for everyone, the documentation can be less confusing .

allows you to do much more than simple profiling. Table 10-1 provides the complete list of items you can be notified about when you write a program using the Profiling API. It's relatively trivial to get these notifications, so you'll probably see all sorts of very neat tools in the future.

The predefined XML schema for configuration files fits the bill in most cases, but when you have complex and structured information to preserve across application sessions, none of the existing schemas appear to be powerful enough. At this point, you have two possible workarounds. You can simply avoid using a standard configuration file and instead use a plain XML file written according to the schema that you feel is appropriate for the data. Alternatively, you can embed your XML configuration data in the standard application configuration file but provide a tailor-made configuration section handler to read it. A third option exists. You could insert the data in the configuration file, register the section with a null handler (IgnoreSectionHandler), and then use another piece of code (for example, a custom utility) to read and write the settings. Before we look more closely at designing and writing a custom configuration handler according to the XML schema you prefer, let's briefly compare the various approaches. In terms of performance and programming power, all approaches are roughly equivalent, but some key differences still exist. In theory, using an ad hoc file results in the most efficient approach because you can create made-to-measure, and subsequently faster, code. However, this is only a possibility if your code happens to be badly written, the performance of your whole application might still be bad. The System.Configuration classes are designed to serve as a general-purpose mechanism for manipulating settings. They work great on average but are not necessarily the best option when an effective manipulation of the settings is key to your code. On the other hand, the System.Configuration classes, and the standard configuration files, require you to write a minimal amount of code. The more customization you want, the more code you have to write, with all the risks (mostly errors and bugs) that this introduces. As a rule of thumb, using the standard configuration files should be the first option to evaluate. Resort to custom files only if you want to control all aspects of data reading (for example, if you want to provide feedback while loading), if performance is critical, or if you just don't feel comfortable with the predefined section handlers. Finally, although it's reasonable to use the IgnoreSectionHandler handler in the context in which the .NET Framework uses it, I don't recommend using IgnoreSectionHandler in user applications. A custom section handler or a custom file is preferable. If you're considering creating a custom file based on a customized XML schema, DataSet objects present an interesting option. Assuming that the data to be stored lends itself to being represented in a tabular format, you could write an XML configuration file using the Microsoft ADO.NET normal form and load that data into a DataSet object. Loading data requires a single call to the ReadXml method, and managing data is easy due to the powerful interface of the DataSet class. We'll look at an example of the DataSet section handler next. Note In the section "Customizing Attribute Names," on page 645, we analyzed a custom section handler inherited from the NameValueSectionHandler class. That trivial handler was simply aimed at overriding some of the standard features of one of the predefined handlers. A truly custom section handler is a more sophisticated object that uses an XML reader to access a portion of the configuration file and parse the contents. 522

and delete all key-value pairs in your domain like this: