vb.net barcode generator free Configuring and Managing Remote Access in .NET

Display qr bidimensional barcode in .NET Configuring and Managing Remote Access

The compiler automatically generates names for these methods by prepending get_ or set_ to the property name specified by the developer. C# has built in support for properties. When the C# compiler sees code that s trying to get or set a property, the compiler actually emits a call to one of these methods. If you re using a programming language that doesn t directly support properties, you can still access properties by calling the desired accessor method. The effect is exactly the same; it s just that the source code doesn t look as pretty. In addition to emitting the accessor methods, compilers also emit a property definition entry into the managed module s metadata for each property defined in the source code. This entry contains some flags and the type of the property, and it refers to the get and set accessor methods. This information exists simply to draw an association between the abstract concept of a "property" and its accessor methods. Compilers and other tools can use this metadata, which can be obtained by using the System.Reflection.PropertyInfo class. The CLR doesn t use this metadata information, though, and requires only the accessor methods at run time. You should use properties only for operations that execute quickly because the syntax to access a property is identical to the syntax for accessing a field. Code with this syntax traditionally doesn t take long to execute; use methods for operations that require more execution time. For example, calculating the area of a rectangle is fast, so it would make sense to use a read only property. But calculating the number of elements in a linked list collection might be quite slow, so you might want to use a method instead of a read only property. For simple get and set accessor methods, the JIT compiler inlines the code so that there s no run time performance hit as a result of using properties rather than fields. Inlining is when the code for a method (or accessor method, in this case) is compiled directly in the method that is making the call. This removes the overhead associated with making a call at run time at the expense of making the compiled method s code bigger. Because property accessor methods typically contain very little code, inlining them can make code smaller and can make it execute faster.

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public class Global : System.Web.HttpApplication { protected void Application_Error(object sender, EventArgs e) { Exception ex = Server.GetLastError(); // display the exception System.Diagnostics.Debug.WriteLine("Error in app: " + ex); // display the exception System.Diagnostics.Debug.WriteLine("Error in app: " + ex); if (ex is HttpUnhandledException) { Context.ClearError(); Server.Transfer("somethingbadhappened.htm"); } else {} } }

You can use the following questions to test your knowledge of the information in Lesson 1, Understanding Web Communications. The questions are also available on the companion CD in a practice test, if you prefer to review them in electronic form.

Here s the short version of the theory and practice of access routines: Hide data in a class. Declare that data using the static keyword or its equivalent to ensure there is only a single instance of the data. Write routines that let you look at the data and change it. Require code outside the class to use the access routines rather than working directly with the data. For example, if you have a global status variable g_globalStatus that describes your program s overall status, you can create two access routines: globalStatus.Get() and globalStatus.set(), each of which does what it sounds like it does. Those routines access a variable hidden within the class that replaces g_globalStatus. The rest of the program can get all the benefit of the formerlyglobal variable by accessing globalStatus.Get() and globalStatus.Set().

// The following line fails to compile, producing // error CS0165: Use of unassigned local variable x . AddVal(ref x);

In the rst target PrintTypeName, the batching is using the Type and Name metadata values. Since the Name metadata is unique, we would expect that the Message task be executed once for each value in the Server item list. From the results shown in Figure 6-16, you can see that this is indeed the case. This also hold true for the PrintTypeNameEnv target, which extends the rst target by also batching on the Env metadata value. There is no limit on the number of metadata values that can be used for a task. Now we will take a look at why MSBuild allows batching expressions to be expressed without an item list name.

If your copy of Windows Server 2008 does not have the RTM version of Hyper-V, please download and copy the RTM version to the server, and run the install. The le can be downloaded from the link in Microsoft Knowledge Base article 950050 at http://support.microsoft.com/kb/950050/. Run the following command and then restart the server as requested: