Some developers
require months to learn everything there is to know about the scripting
language and the objects the language controls. This section helps you
understand the various objects that WSH supports. You won't become a
guru overnight. As you learn more, you'll be able
to create scripts of increasing complexity. Scripting isn't hard to
learn, but you need to take your time and learn it a bit at a time.
WSH depends on
objects that Microsoft supplies as part of Windows to perform tasks such
as outputting text to the display.
NOTE
An object
consists of three elements: properties, methods, and events. A property
describes the object and determines its functionality. For example, you
can say an apple is red. In this case, red is a property of the apple.
However, you can also paint the apple blue. In this case, you changed
the color property of the apple to another value. Methods are actions
you can perform with an object. For example, looking at an apple again,
you can say that it has a grow method. As the tree applies the grow
method, the apple becomes larger. Events are responses to specific
object actions. For example, when the apple becomes mature, it raises
the "color" event to tell you that it's ripe.
Writing scripts in
Windows means knowing the object you want to work with, the properties
that object provides, and the methods you can use with that object. You
don't have to know about every object. In fact, you'll find it easier to
learn about one object at a time. The following sections tell you about
the main scripting object, WScript, and some of the supporting objects
it contains.
1. Working with the WScript Object
The WScript
object is the main object for WSH. You'll access every other object
through this one. The following list tells you about the properties that
the WScript object supports.
Application Provides you with
access to a low level interface for WScript. An interface is a pointer
to a list of functions that you can call for a particular object. Only
advanced programmers need this property because WSH exposes all of the
basic functions for you.
Arguments Provides a complete
list of the arguments for this script. Applications pass arguments on
the command line. WSH passes the argument list as an array. You create a
variable to hold the argument list, and then access the individual
arguments as you would any array. The Arguments.Count property contains
the total number of array elements.
FullName Contains the full
name of the scripting engine along with the fully qualified path to it.
For example, if you were using CScript, you might get C:\WINDOWS\SYSTEM32\CSCRIPT.EXE as a return value.
Interactive Returns true if the script is in interactive mode.
Name Returns the friendly name for WScript. In most cases, this is Windows Script Host.
Path Provides just the
path information for the host executable. For example, if you were using
CScript, you may get a return value of: C:\WINDOWS\SYSTEM32\.
ScriptFullName Contains the full name and path of the script that's running.
ScriptName Provides just the script name.
Version Returns the WSH Version number.
Remember that all of these properties tell you about the WScript object. You can also use methods to perform tasks with the WScript
object. The following list provides a brief overview of the more
important methods you'll use with the WScript object. Note that most of
these methods require you pass one or more parameters as input. A
parameter is a piece of data the method uses to perform a task.
CreateObject (strProgID)Create the object specified by strProgID. This object could be WSH specific like "WScript.Network" or application specific like "Excel.Application".
GetObject (strPathname[,strProgID])Retrieves the
requested object. strPathname contains the filename for the object you
want to retrieve. In most cases, this is going to be a data file, but
you can retrieve other kinds of objects as well. As soon as you execute
this command, WSH starts the application associated with that object.
For example, if you specified C:\MyText.TXT as the strPathname, then WSH may open Notepad to display it. The optional strProgID
argument allows you to override the default processing of the object.
For example, you may want to open the text file with Word instead of
Notepad.
Echo (AnyArg)Displays text in a window (WScript) or to the console screen (CScript). AnyArg
can contain any type of valid output value. This can include both
strings and numbers. Using Echo without any arguments displays a blank
line.
GetScriptEngine (strEngineID)Registers an alternative script engine such as PerlScript . strEngineID contains the identifier
for the script engine that you want to retrieve. You'll need to register
the engine using the GetScriptEngine.Register() method before you can actually use it. A script engine also requires you to provide a default extension.
Quit (intErrorCode)Exits the script prematurely. The optional intErrorCode argument returns an error code if necessary. You can test for this value using the ErrorLevel clause in batch files.
2. Working with the WScript.WshArguments Object
Whenever you start a script, you have the option of passing one or more arguments to it on the command line. That's where the WshArguments
object comes into play. It helps you determine the number of arguments,
and then retrieve them as needed. You'll always use the WScript.Arguments property to access this object; it's not directly accessible. The following list describes the properties for this object.
Item (intIndex)Retrieves a specific command line argument. intIndex
contains the index of the argument that you want to retrieve. The array
used to hold the arguments is 0 based, so the first argument number is
0.
Count() Returns the number of command line arguments.
Length() Returns the number of command line arguments. WSH provides this property for JScript compatibility purposes.
3. Working with the WScript.WshShell Object
You'll use the WScript.WshShell
object to access the Windows shell (the part of Windows that interacts
with applications and creates the user interface) in a variety of ways.
For example, you can use this object to read the registry or to create a
new shortcut on the desktop. This is an exposed WSH object, which means
you can access it directly. However, you need to access it through the WScript object like this: WScript.WshShell. The following list describes the WshShell methods.
CreateShortcut (strPathname)Creates a WSH shortcut object. strPathname contains the location of the shortcut, which will be the Desktop in most cases.
DeleteEnvironmentVariable (strName[,strType])Deletes the environment variable specified by strName. The optional strType argument defines the type of environment variable to delete. Typical values for strType include System, User, Volatile, and Process. The default environment variable type is System.
GetEnvironmentVariable (strName [, strType])Retrieves the environment variable specified by strName. Default environment variables include NUMBER_OF_PROCESSORS, OS, COMSPEC, HOMEDRIVE, HOMEPATH, PATH, PATHEXT, PROMPT, SYSTEMDRIVE, SYSTEMROOT, WINDIR, TEMP, and TMP. The optional strType argument defines the type of environment variable to delete. Typical values for strType include System, User, Volatile, and Process. The default environment variable type is System.
Popup (strText [,intSeconds] [,strTitle] [,intType])Displays a message
dialog box. The return value is an integer defining which button the
user selected including the following values: OK (1), Cancel (2), Abort
(3), Retry (4), Ignore (5), Yes (6), No (7), Close (8), and Help (9). strText contains the text that you want to display in the dialog box. intSeconds determines how long WSH displays the dialog box before it closes the dialog box and returns a value of −1. strTitle contains the title bar text. The intType argument can contain values that determine the type of dialog box you'll create. The first intType
argument determines button type. You have a choice of OK (0), OK and
Cancel (1), Abort, Retry, and Ignore (2), Yes, No, and Cancel (3), Yes
and No (4), and Retry and Cancel (5). The second intType
argument determines which icon Windows displays in the dialog box. You
have a choice of the following values: Stop (16), Question (32),
Exclamation (48), and Information (64). Combine the intType argument values to obtain different dialog box effects.
RegDelete (strName)Removes the value or key specified by strName from the registry. If strName ends in a backslash, then RegDelete removes a key. You must provide a fully qualified path to the key or value that you want to delete. In addition, strName must begin with one of these values: HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE, HKEY_CLASSES_ROOT, HKEY_USERS, HKEY_CURRENT_CONFIG, or HKEY_DYN_DATA.
RegRead (strName)Reads the value or key specified by strName from the registry. If strName ends in a backslash, then RegRead reads a key. You must provide a fully qualified path to the key or value that you want to read. In addition, strName must begin with one of these values: HKEY_ CURRENT_USER, HKEY_LOCAL_MACHINE, HKEY_CLASSES_ROOT, HKEY_USERS, HKEY_CURRENT_CONFIG, or HKEY_DYN_DATA. RegRead can only read specific data types including REG_SZ, REG_EXPAND_SZ, REG_DWORD, REG_BINARY, and REG_MULTI_SZ. Any other data types will return an error.
RegWrite (strName, anyValue [, strType])Writes the data specified by anyValue to a value or key specified by strName to the registry. If strName ends in a backslash, then RegWrite writes a key. You must provide a fully qualified path to the key or value that you want to write. In addition, strName must begin with one of these values: HKEY_CURRENT_USER, HKEY_LOCAL_ MACHINE, HKEY_CLASSES_ROOT, HKEY_USERS, HKEY_CURRENT_CONFIG, or HKEY_DYN_DATA. RegRead can only write specific data types including REG_SZ, REG_EXPAND_SZ, REG_DWORD, and REG_BINARY. Any other data types will return an error.
Run (strCommand [, intWinType] [lWait])Runs the command or application specified by strCommand. You can include command line arguments and switches with the command string. intWinType
determines the type of window that the application starts in. You can
force the script to wait for the application to complete by setting lWait to True; otherwise, the script begins the next line of execution immediately.
SetEnvironmentVariable (strName, strValue [, strType])Sets the environment variable named strName to the value specified by strValue. The optional strType argument defines the type of environment variable to create. Typical values for strType include System, User, Volatile, and Process. The default environment variable type is System.
4. Working with the WScript.WshNetwork Object
The WshNetwork object
works with network objects such as drives and printers that the client
machine can access. This is an exposed WSH object, which means you can
access it directly using the WScript.WshNetwork object. The following list describes properties associated with this object.
ComputerName Returns a string containing the client computer name.
UserDomain Returns a string containing the user's domain name.
UserName Returns a string containing the name that the user used to log on to the network.
As with any other WSH object, the WshNetwork object uses methods to work with network resources. The following list describes the methods associated with this object.
AddPrinterConnection (strLocal, strRemote [, lUpdate] [, strUser] [, strPassword])Creates a new printer connection for the local machine. strLocal contains the local name for the printer specified by strRemote. The strRemote value must contain a locatable resource and usually uses a UNC format such as \\Remote\Printer. Setting lUpdate
to True adds the new connection to the user profile, which means
Windows makes the connection available each time the user boots their
machine. strUser and strPassword contain optional username and password values required to log onto the remote machine and create the connection.
EnumNetworkDrives() Returns a WshCollection object containing the list of local and remote drives currently mapped from the client machine. A WshCollection object is essentially a 0-based array of strings.
EnumPrinterConnections() Returns a WshCollection object containing the list of local and remote printers currently mapped from the client machine. A WshCollection object is essentially a 0-based array of strings.
MapNetworkDrive (strLocal, strRemote [, lUpdate] [, strUser] [, strPassword])Creates a new drive connection for the local machine. strLocal contains the local name for the drive specified by strRemote. The strRemote value must contain a locatable resource and usually uses a UNC format such as \\Remote\Drive_C. Setting lUpdate
to True adds the new connection to the user profile, which means
Windows makes the connection available each time the user boots their
machine. strUser and strPassword contain optional username and password values required to log onto the remote machine and create the connection.
RemoveNetworkDrive (strName [, lForce] [, lUpdate])Deletes a previous network drive mapping. If strName contains a local name, Windows only cancels that connection. If strName contains a remote name, then Windows cancels all resources associated with that remote name. Set lForce to True if you want to disconnect from a resource whether that resource is in use or not. Setting lUpdate
to True removes the connection from the user profile so that it doesn't
appear the next time that the user logs onto the machine.
RemovePrinterConnection (strName [, lForce] [, lUpdate])Deletes a previous network printer connection. If strName contains a local name, Windows only cancels that connection. If strName contains a remote name, then Windows cancels all resources associated with that remote name. Set lForce to True if you want to disconnect from a resource whether that resource is in use or not. Setting lUpdate
to True removes the connection from the user profile so that it doesn't
appear the next time that the user logs onto the machine.
|
