Simple .NET/ASP.NET PDF document editor web control SDK
We ll examine all the pieces shown here in due course, but for now, note that even this simplest of examples depends on a class from the library the System.Console class in this case to do its job. Finally, the class library offers whole frameworks to support building certain kinds of applications. For example, Windows Presentation Foundation (WPF) is a framework for building Windows desktop software; ASP.NET (which is not an acronym, despite appearances) is a framework for building web applications. Not all frameworks are about user interfaces Windows Communication Foundation (WCF) is designed for building services accessed over the network by other computer systems, for instance. These three categories are not strict, as quite a few classes fit into two. For example, the parts of the class library that provide access to the filesystem are not just thin wrappers around existing Win32 APIs. They add new object-oriented abstractions, providing significant functionality beyond the basic file I/O services, so these types fit into both the first and second categories. Likewise, frameworks usually need to integrate with underlying services to some extent for example, although the Windows Forms UI framework has a distinctive API of its own, a lot of the underlying functionality is provided by Win32 components. So the three categories here are not strict. They just offer a useful idea of what sorts of things you can find in the class libraries.barcode fonts for excel 2016, excel barcode font microsoft, barcode activex control for excel 2010, free barcode generator excel 2003, excel 2010 barcode control, barcode add-in for word and excel 2010, microsoft excel 2013 barcode add in, free barcode fonts for microsoft office, how to create barcodes in excel 2010, make barcodes excel 2003,
While we re looking at the structure and layout of source code, we need to examine a language feature that is extremely important, despite having precisely no effect on the behavior of your code. C# lets you add text to your source file that it will completely ignore. This might not sound important, or even useful, but it turns out to be vital if you want to have any hope of understanding code you wrote six months ago. There s an unfortunate phenomenon known as write-only code. This is code that made some kind of sense to whoever wrote it at the time, but is incomprehensible to anyone trying to read it at a later date, even if the person reading it is its author. The best defense against this problem is to think carefully about the names you give the
With the odd exception: in a string constant such as the Hello, world text in this example, whitespace is treated literally C# presumes that if you put, say, three spaces in some text enclosed in double quotes, you really want three spaces.
The user interface has evolved along a cyclical path from a light footprint to a heavy footprint and back again. Users requirements and demands for extra functionality drive the heavier footprint, and users requirements and demands for an easy installation, upgrade, and maintenance drive the lighter footprint. With each iteration, the lighter user interfaces gain rich functionality, and the heavier user interfaces become easier to install, upgrade, and maintain. The original user interfaces were probably the lightest clients of all punch cards that were fed into a central server that in turn printed results, resulting in a simple request/ response architecture (see Figure 1-1). As computers became more sophisticated, the punch card and printer were replaced by a terminal that fed results into and rendered results from the central server (see Figure 1-2). For basic processing this was useful, but as computers needs increased for example, to handle the new requirements of email or network news the terminals had to get smarter. If you remember the old terminal-based email programs such as elm or the network newsreaders, you ll remember needing three or four extra fingers to do anything useful! Architecturally, this wasn t much different from the punch card request/response architecture, but it unified the point of contact with the mainframe and changed the medium from paper to electrons. So, although the architecture did not change, the implementation did and it was this change in implementation that was a driving factor in improving the overall user experience of applications, a fact that is still true today.
features of your code and the way you structure your programs. You should strive to write your code so that it does what it looks like it does. Unfortunately, it s sometimes necessary to do things in a nonobvious way, so even if your code is sufficiently clear that it s easy to see what it does, it may not be at all clear why it does certain things. This tends to happen where your code meets other code you might be interacting with a component or a service that s idiosyncratic, or just plain buggy, and which works only if you do things in a particular way. For example, you might find that a component ignores the first attempt to do something and you need to add a redundant-looking line of code to get it to work:
The problem with this sort of thing is that it s very hard for someone who comes across this code later on to know what to make of it. Is that apparently redundant line deliberate Is it safe to remove Intrigue and ambiguity might make for engaging fiction, but these characteristics are rarely desirable in code. We need something to explain the mystery, and that s the purpose of a comment. So you might write this: