Recipe 2.15. Getting System Information

Problem

You've heard that .NET provides powerful access to the most essential features of Windows, but the Framework Class Library is huge, and you're not sure where to find the total amount of memory installed on the local system. How can you get system-specific information quickly and easily?

Solution

Use the various objects and members of Visual Basic's My namespace. Microsoft introduced this new feature in the 2005 release of the language.

Discussion

The My namespace was added to Visual Basic to help restore some of the simplicity and accessibility of Visual Basic that was lost in its transition to .NET.

For example, to determine the amount of installed memory on the local system, use the following statement:

 Dim installedMemory As Long = _    My.Computer.Info.TotalPhysicalMemory

Another useful source of system settings is the System.Windows.Forms. SystemInformation object, which has dozens of informative members.

The My hierarchy makes an incredible number of features available in one easy-to-access place. Table 2-1 includes a small sampling of the information you can obtain from the My namespace.

Table 2-1. A sampling of My features
If you need to access this information…	…use this My namespace member
The command-line arguments used to start the program	`My.Application.CommandLineArgs`
The application version number	`My.Application.Info.Version`
The set of all forms currently open	`My.Application.OpenForms`
Features to read and write clipboard data	`My.Computer.Clipboard`
The current value of the system timer	`My.Computer.Clock.TickCount`
The current directory recognized by the application	`My.Computer.FileSystem.CurrentDirectory`
The location of the user's "My Documents" directory	`My.Computer.FileSystem.SpecialDirectories.MyDocuments`
The directory used to store the user's temporary files	`My.Computer.FileSystem.SpecialDirectories.Temp`
The version of the operating system	`My.Computer.Info.OSVersion`
Total installed memory	`My.Computer.Info.TotalPhysicalMemory`
Whether the user's mouse has a scroll wheel installed	`My.Computer.Mouse.WheelExists`
The assigned name of the computer	`My.Computer.Name`
Whether access to Internet or the local network is enabled	`My.Computer.Network.IsAvailable`
The assigned name of the current Windows user	`My.User.Name`

The My namespace collects some of the most useful and (sometimes) complex areas of the .NET Framework Class Libraries and makes them available in a simpler and more ordered format. The My keyword, a new 2005 feature specific to Visual Basic, is at the top of a hierarchy of features that are organized much like .NET namespaces. Each major object node within the hierarchy implements various properties and methods that are relevant to the specific object. In most cases, each method or property can be found somewhere else in the large set of .NET classes, although it may take several source code steps to obtain the information you need from that distant member.

The following list of objects summarizes the features exposed through the My hierarchy:

My.Application: Provides access to application- and instance-specific settings, such as commandline arguments, and in-effect regional and language settings.
My.Application.Info: Reports details about the active executing assembly, including its title and version number.
My.Application.Log: Provides access to trace recording and logging features for desktop and console applications (not ASP.NET).
My.Computer: Exposes information pertaining to the computer running the application. Most of the members of this object are other subordinate objects with their own methods and properties.
My.Computer.Audio: Enables you to play system and file-based sounds.
My.Computer.Clipboard: Provides access to features that let you place data on the system clipboard and retrieve data back from that same clipboard in a variety of common and custom data formats.
My.Computer.Clock: Provides access to the current system time in a standard or local format.
My.Computer.FileSystem: Provides access to various features that let you manage files and directories on local and remote file systems and that manipulate path strings.
My.Computer.FileSystem.SpecialDirectories: Reports locations of the various special directories, such as the "My Documents" directory.
My.Computer.Info: Reveals information about the local operating system and memory usage.
My.Computer.Keyboard: Reports the current state of the keyboard.
My.Computer.Mouse: Reports various properties of the installed mouse.
My.Computer.Network: Reports availability of the network connection on the current workstation, and provides features that let you transfer data over that network.
My.Computer.Ports: Provides access to the system serial ports.
My.Computer.Registry: Provides features that let you manage the keys and values within the Windows registry.
My.Forms: Provides access to all forms defined in the active Windows Forms application.
My.Log: Provides access to trace recording and logging features for ASP.NET applications only.
My.Request: Replicates the Active Server Pages "Request" object within an ASP.NET application.
My.Resources: Provides access to application-specific resources, including string, graphic, and binary resource data.
My.Response: Replicates the Active Server Pages "Response" object within an ASP.NET application.
My.Settings: Provides access to system- and user-focused configuration settings used by the application and automatically stored in application-specific XML configuration files.
My.User: Contains authentication and identity details gathered about the current user, either through Windows authentication or some other authentication scheme.
My.WebServices: Contains a collection of all XML web services known to the active application. This object is not available in ASP.NET applications; it is only used by Windows Forms, console, and other non-web application types.

Problem

Solution

Discussion

Table 2-1. A sampling of My features

See Also