barcode generator in asp.net code project Part I CLR Basics in .NET

Print qr bidimensional barcode in .NET Part I CLR Basics

An IP address within a defined scope that is offered to a DHCP client is known as a lease. When a lease is made to a client, the lease is active. Each lease has a specified duration, and the client must periodically renew the lease if the client is going to con tinue to use the address. The default lease duration value is eight days. Leases can be renewed for a variety a reasons. First, a client automatically attempts to renew its lease after 50 percent of the client lease time elapses. A client also attempts to renew a lease upon restarting. When a DHCP client shuts down and restarts, it typ ically obtains a fresh lease for the same IP address it had prior to the shutdown. Finally, leases are refreshed when you execute the Ipconfig /renew command from a DHCP client computer. You create scopes in DHCP by using the New Scope Wizard, which you can launch by right-clicking the DHCP server node in the DHCP console and then selecting New Scope from the Action menu. The pages of the New Scope Wizard listed next allow you to configure the correspond ing scope features:

If the error handler is set to null, the default error handler will fire and display the default Silverlight error message, as shown in Figure 6-1.

If you were to compile this code and examine the resulting assembly with ILDasm .exe, you d see that the C# compiler did, in fact, emit a protected override method named Finalize into the module s metadata . If you examined the Finalize method s IL code, you d also see that the code inside the method s body is emitted into a try block, and that a call to base. Finalize is emitted into a finally block . Important If you re familiar with C++, you ll notice that the special syntax C# requires for

Note When the GridView control fires the Sorting event, the SortExpression and SortDirection properties haven t been updated yet. When Sorted fires, the properties are up-to-date. If you click twice on the same column, the SortDirection property will contain, say, Ascending in Sorting and Descending in Sorted.

Never give external vendors access to an existing administrator account. Instead always set up a separate, dedicated account for vendors needing remote access. Furthermore, if external printer or scanner vendors ask for a listing of all user names, passwords, and IP addresses on the network to be faxed to their network engineers to set up the device ahead of time, kindly say no and send a request for proposals to a different vendor.

ASP.NET, in conjunction with some other services available as part of the .NET Framework, allows this transition to take place much more cleanly. (See MSDN for information about the Microsoft Application Center, one service that can help with this kind of upgrading.) As for the components themselves, new ASP.NET components are designed to be copied on top of the older versions, and users connected to an old version are allowed to cleanly spin down, while new requests will receive the new component. Of course, potential problems still lurk, but the ability to copy in a new component without shutting down services like IIS and Component Services is a huge advance. Finally, the fourth problem is developing and debugging COM components, which is a difficult process. Developing COM components using Visual Basic is definitely easier than using C++, but it s still more difficult than it should be. Debugging COM components that are called from an ASP page isn t impossible, but it involves a very different process than standard ASP script debugging. ASP.NET components address all these issues and more, as you ll see in this chapter. But first, let s take a look at exactly what makes up a component in ASP.NET.

Player can perform this conversion on the fly when synchronizing with a portable device, allowing you to keep higher-quality copies on your computer . Thankfully, hard disk storage is no longer the limiting factor for digital music collections that it once was, making higher bit rates (and higher file sizes) much more palatable . For most users who care about music, the WMA default rate of 128 Kbps is the minimum acceptable choice . If you re a discerning audiophile with high-quality playback equipment, you will almost certainly want to choose a higher bit rate . If you prefer the MP3 format, we recommend a minimum bit rate of at least 192 Kbps; if you prefer the efficiency and audio quality of variable bit-rate MP3 encoding, you ll need to use a third-party product that supports this encoding method and then add the tracks to the library . To determine your own minimum acceptable audio quality, you ll need to perform comparative tests using your own ears and speakers .

Click Next to open the Type Your Network Administrator User Name And Password page of the Connect Computer Wizard. Enter the credentials for a Network Administrator account.

writer.WriteStartDocument(); writer.WriteStartElement("array"); foreach(string s in theArray) { writer.WriteStartElement("element"); writer.WriteAttributeString("value", s); writer.WriteEndElement(); } writer.WriteEndDocument(); The root node is array and contains a series of child nodes named element, each with an attribute value, as shown here: < xml version="1.0" > <array> <element value="Rome" /> <element value="New York" /> <element value="Sydney" /> <element value="Stockholm" /> <element value="Paris" /> </array> The element node is created entirely in the loop. If you don't explicitly close it by calling WriteEndElement, the final output would look like this: < xml version="1.0" > <array> <element value="Rome"> <element value="New York"> <element value="Sydney"> <element value="Stockholm"> <element value="Paris" /> </element> </element> </element> </element> </array> Writing Raw XML Data As we've seen, the XML writer saves the developer from a lot of the details concerning the markup text in an XML document. So what happens if you try to run the following command writer.WriteString("<");

Notice the second line of code. After the control has been loaded, it needs to be added to the Form object for display and use.