VBScript11

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VBScript
Session 11
Dani Vainstein
1
What we learn last session?
VBScript
VBScript
VBScript
VBScript
Dani Vainstein
string manipulation.
string math.
date manipulation.
Formatting Strings.
2
Subjects for session 11
The OOP model.
Objects.
COM objects.
Set statement.
Nothing keyword
CreateObject function.
New keyword.
FileSystem object.
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3
OOP Model
Abstractions
Encapsulation
Polymorphism
Inheritance
Reusabillity
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OOP Model
Abstractions
The ability for a program to ignore some aspects of the
information it's manipulating, i.e. the ability to focus on the
essential.
An abstract class cannot be instantiated.
An abstract class may contain abstract methods and accessors.
An abstract class can be partially implemented, or not at all
implemented.
Abstract classes are useful when creating components because
they allow you specify an invariant level of functionality in some
methods, but leave the implementation of other methods until a
specific implementation of that class is needed.
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OOP Model
Encapsulation
The ability for the program to hide
information about the implementation of a
module from its users, i.e. the ability to
prevent users from breaking the invariants
of the program.
The term encapsulation refer to
Information hiding in software.
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OOP Model
Polymorphism
Polymorphism is the ability for classes to
provide different implementations of
methods that are called by the same
name.
Polymorphism allows a method of a class
to be called without regard to what
specific implementation it provides.
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OOP Model
Polymorphism
• You might have a class named Road which calls the Drive
method of an additional class.
• This Car class may be SportsCar, or SmallCar, but both
would provide the Drive method.
• Though the implementation of the Drive method would
be different between the classes, the Road class would
still be able to call it, and it would provide results that
would be usable and interpretable by the Road class.
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OOP Model
Inheritance
Defining classes as extensions of existing
classes.
In computer science, the term
inheritance may be applied to a variety
of situations in which certain
characteristics are passed on from one
context to another.
The term originates with the
biological concept of a parent passing on
certain traits to a child
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Dimensions
Flanks
Area
Shape
Perimeter
Radious
*pi
Circle
Height
Width
angles
Rectangle
Triangle
Where is the
right place for
this action?
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Volume
3D
depth
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OOP Model
Reusabillity
reusability is the likelihood a segment of structured code can be
used again to add new functionalities with slight or no
modification.
Reusable code reduces implementation time, increases the
likelihood that prior testing and use has eliminated bugs and
localizes code modifications when a change in implementation is
required.
Subroutines or functions are the simplest form of reuse.
A chunk of code is regularly organized using module or
namespace.
Proponents claim that objects and software components offer a
more advanced form of reusability.
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Object Model
Object.
Collection.
Container object.
Method.
Event.
Property.
Attribute.
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Object Model
Objects
In computer science , an object is a data structure (incorporating
data and methods) whose instance is unique and separate from
other objects, although it can "communicate" with other objects.
In some occasions, some object can be conceived of as a sub
program which can communicate with others by receiving or giving
instructions based on its, or the other's, data or methods. Data can
consist of numbers, literal strings , variables, and references.
the object lifetime (or life cycle) of an object in OOP is the
time between an object's creation (also known as instantiation or
construction) till the object is no longer used, and is destructed
or freed.
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Object Model
Collection
An object that contains zero or more objects
(member).
Collections normally contain objects of the same
class.
Also referred to as a collection object or an
object collection.
Collection has normally two single read-only
properties, Item and Count
you usually use the Item property or method
and pass the name or index number of the
member.
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Object Model
Container Object
An object that contains other objects
from different classes.
Collection can have properties and/or
methods.
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Object Model
Methods
Method is a function or subroutine that is associated
with a class in OPP.
Like a function in procedural languages, it may contain
a set of program statements that perform an action,
and (in most computer languages ) can take a set of
input arguments and can return some kind of result.
The purpose of a method is to provide a mechanism
for changing or accessing information stored in an
object of the class.
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Object Model
Methods
A method should preserve invariants associated with
the class, and should be able to assume that every
invariant is valid on entry to the method
A method can have parameters.
method may produce output, which are constrained by
postconditions of the method.
If the arguments to a method do not satisfy their
preconditions, a method can raise an exception
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Object Model
Event
In the context of programming, the occurrence
of some particular action or the occurrence of a
change of state that can be handled by an
application or COM object that is invoked in
response to the triggering of an event. .
For example, the arrival of a message to the
SMTP service is an event that can be handled by
any number of Applications or objects.
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Object Model
Property
Properties are like smart fields.
A property is an information that is associated with an
object.
Each property has a value. value is a keyword in the
syntax for the property definition.
The variable value is assigned to the property in the
calling code.
The type of value must be the same as the declared
type of the property to which it is assigned.
properties fall into two categories: run-time properties
and persistent properties.
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Object Model
Attribute
Each property has attributes.
Attributes provide information about the property.
For example, the First Name property has the following
attributes: Name, Display Name, Description, and Type.
Attributes include information such as the data type of
the profile property (for example, number, text, decimal,
or site term), and whether the property is single-valued
(for example, only one First Name entry is allowed per
user) or multi-valued.
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COM
Component Object Model
An architecture for defining interfaces (a set of abstract
methods and properties that encompass some common
purpose) and interaction among objects implemented by
widely varying software applications.
All COM interfaces are extend and derived from the
IUnknown, interface which includes the methods
QueryInterface, AddRef, and Release.
COM interfaces additionally define a binary signature that
acts as a contract between the interface designer and client
applications written to use the interface COM classes
provide concrete implementations of COM interfaces.
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COM
IUnknown
The fundamental COM interface, which must be
extended by every valid COM interface.
IUnknown exposes three methods:
QueryInterface, used to find out if the object
supports a certain interface and return the interface if
it does.
AddRef, to increment the interface reference count.
Release, to decrement the interface reference count.
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COM
COM Class
An implementation of one or more COM
interfaces.
COM objects are instances of COM
classes.
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COM
COM Interface
A pointer to a vtable pointer where the
first three methods in that table are
QueryInterface, AddRef, and Release.
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COM Objects
COM Extensions Technologies
COM+(Component Services )
ActiveX, OLE
SOM, DSOM – IBM’s System object model
DCOM (Distributed COM)
Distributed COM
CORBA – Common Object Request Broker
Architecture
RMI, JavaBeans – SUN Microsystems
technologies.
RPC – Remote Procedure Call.
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COM objects
Where they are?
In the registry under HKEY_CLASSES_ROOT you
will se all the classes registered in your system.
You can find there the Scripting.FileSystemObject
Key, Excel.Application key etc
All those classes can be used in VBScript.
Each class has a description, a CLSID entry and
some a version entry.
In CLSID you will find the class identifier.
If you move to HKEY_CLASSES_ROOT\CLSID you
will see wich dll’s using this class.
For more information search for <registration>
Element topic in VBScript documentation.
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Set statement
Assigns an object reference to a variable or property, or associates a procedure
reference with an event.
To be valid, object must be an object type consistent with the object being
assigned to it.
The Dim, Private, Public, or ReDim statements only declare a variable that
refers to an object.
No actual object is referred to until you use the Set statement to assign a
specific object.
Generally, when you use Set to assign an object reference to a variable, no
copy of the object is created for that variable.
Instead, a reference to the object is created.
More than one object variable can refer to the same object.
Because these variables are references to (rather than copies of) the object, any
change in the object is reflected in all variables that refer to it.
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Nothing Keyword
The Nothing keyword in VBScript is used to disassociate an object
variable from any actual object.
Use the Set statement to assign Nothing to an object variable. For
example:
Set MyObject = Nothing
Several object variables can refer to the same actual object.
When Nothing is assigned to an object variable, that variable no
longer refers to any actual object.
When several object variables refer to the same object, memory and
system resources associated with the object to which the variables
refer are released only after all of them have been set to Nothing,
either explicitly using Set, or implicitly after the last object variable set
to Nothing goes out of scope.
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CreateObject Function
CreateObject(servername.typename [, location])
Creates and returns a reference to an Automation object.
servername - Required. The name of the application providing
the object.
typename - Required. The type or class of the object to create.
location - Optional. The name of the network server where the
object is to be created.
Automation servers provide at least one type of object.
For example, a word-processing application may provide an
application object, a document object, and a toolbar object.
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CreateObject Function
For example, a word-processing
application may provide an application
object, a document object, and a toolbar
object.
To create an Automation object, assign the
object returned by CreateObject to an
object variable:
Dim ExcelSheet
Set ExcelSheet = CreateObject("Excel.Sheet")
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CreateObject Function
Once an object is created, refer to it in code using the object variable you
defined.
you can access properties and methods of the new object using the object
variable.
Creating an object on a remote server can only be accomplished when
Internet security is turned off.
You can create an object on a remote networked computer by passing
the name of the computer to the servername argument of
CreateObject.
That name is the same as the machine name portion of a share name.
For a network share named "\\myserver\public", the servername is
"myserver". In addition, you can specify servername using DNS format
or an IP address.
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CreateObject Function
Summary
Creating an object
Set myDoc = CreateObject (“Word.Document”)
Using The object
MyDoc.content = “abc”
MyDoc.SaveAs “Doc1.doc”
MyDoc.Close
Free the object
Set Mydoc = Nothing
Type
Library
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COM
Class
32
FileSystemObject Object
Basics
When writing scripts it's often important to add,
move, change, create, or delete folders and
files.
It may also be necessary to get information
about and manipulate drives attached to the
machine.
Scripting allows you to process drives, folders,
and files using the FileSystemObject (FSO)
object model.
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New Keyword
Keyword used to create a new instance of a class.
If objectvar contained a reference to an object, that
reference is released when the new one is assigned.
The New keyword can only be used to create an instance
of a class.
Using the New keyword allows you to concurrently
create an instance of a class and assign it to an object
reference variable.
The variable to which the instance of the class is being
assigned must already have been declared with the Dim
(or equivalent) statement.
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FileSystemObejct Object
Model
The FileSystemObject (FSO) object model allows you to use the
familiar object.method syntax with a rich set of properties, methods,
and events to process folders and files.
The FSO object model gives to the QTP the ability to create, alter,
move, and delete folders, or to detect if particular folders exist, and if
so, where. You can also find out information about folders, such as
their names, the date they were created or last modified, and so forth.
The FSO object model also makes it easy to process files. When
processing files, the primary goal is to store data in a space- and
resource-efficient, easy-to-access format.
You need to be able to create files, insert and change the data, and
output (read) the data.
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FileSystemObejct Object
Model
The FSO object model, which is contained in the
Scripting type library (Scrrun.dll), supports text
file creation and manipulation through the
TextStream object.
Although it does not yet support the creation or
manipulation of binary files, future support of
binary files is planned.
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FileSystemObject Objects
Main
Main object.
Contains methods and properties that allow you to create,
delete, gain information about, and generally manipulate
drives, folders, and files.
Many of the methods associated with this object duplicate
those in other FSO objects; they are provided for
convenience.
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FileSystemObject Objects
Drive Object
Contains methods and properties that allow you to gather
information about a drive attached to the system, such as
its share name and how much room is available.
Note that a "drive" isn't necessarily a hard disk, but can be
a CD-ROM drive, a RAM disk, and so forth. A drive doesn't
need to be physically attached to the system; it can be also
be logically connected through a network.
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FileSystemObject Objects
Drive Collection
Provides a list of the drives attached to
the system, either physically or logically.
The Drives collection includes all drives,
regardless of type.
Removable-media drives need not have
media inserted for them to appear in this
collection.
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FileSystemObject Objects
File Object
Contains methods and properties that
allow you to create, delete, or move a
file.
Also allows you to query the system for a
file name, path, and various other
properties.
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FileSystemObject Objects
Files Collection
Provides a list of all files contained within
a folder.
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FileSystemObject Objects
Folder Object
Contains methods and properties that
allow you to create, delete, or move
folders.
Also allows you to query the system for
folder names, paths, and various other
properties.
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FileSystemObject Objects
Folders Collection
Provides a list of all the folders within a
Folder.
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FileSystemObject Objects
TextStream Object
Allows you to read and write text files.
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Programming the
FileSystemObject
Use the CreateObject method to create
a FileSystemObject object.
Use the appropriate method on the newly
created object.
Access the object's properties.
Set objFSO = CreateObject("Scripting.FileSystemObject")
Scripting is the name of the type library
and FileSystemObject is the name of
the object that you want to create.
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Accessing Existing Drives, Files,
and Folders
To gain access to an existing drive, file, or folder, use the appropriate
"get" method of the FileSystemObject object:
GetDrive
GetFolder
GetFile
Do not use the "get" methods for newly created objects, since the
"create" functions already return a handle to that object.
For example, if you create a new folder using the CreateFolder
method, don't use the GetFolder method to access its properties,
such as Name, Path, Size, and so forth.
Just set a variable to the CreateFolder function to gain a handle to
the newly created folder, then access its properties, methods, and
events.
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Accessing the Object's
Properties
Once you have a handle to an object, you can
access its properties.
For example, to get the name of a particular
folder, first create an instance of the object,
then get a handle to it with the appropriate
method (in this case, the GetFolder method,
since the folder already exists).
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Working with Drives and
Folders
With the FileSystemObject (FSO)
object model, you can work with drives
and folders programmatically just as you
can in the Windows Explorer
interactively.
You can copy and move folders, get
information about drives and folders, and
so forth.
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Getting Information About
Drives
The Drive object allows you to gain
information about the various drives
attached to a system, either physically or
over a network.
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Getting Information About
Drives
The total size of the drive in bytes (TotalSize property).
How much space is available on the drive in bytes (AvailableSpace or
FreeSpace properties).
What letter is assigned to the drive (DriveLetter property).
What type of drive it is, such as removable, fixed, network, CD-ROM, or RAM
disk (DriveType property).
The drive's serial number (SerialNumber property).
The type of file system the drive uses, such as FAT, FAT32, NTFS, and so forth
(FileSystem property).
Whether a drive is available for use (IsReady property)
The name of the share and/or volume (ShareName and VolumeName
properties)
The path or root folder of the drive (Path and RootFolder properties)
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Working With Folders
Create a folder - FileSystemObject.CreateFolder
Delete a folder - Folder.Delete or FileSystemObject.DeleteFolder
Move a folder - Folder.Move or FileSystemObject.MoveFolder
Copy a folder - Folder.Copy or FileSystemObject.CopyFolder
Retrieve the name of a folder - Folder.Name
Find out if a folder exists on a drive - FileSystemObject.FolderExists
Get an instance of an existing Folder object - FileSystemObject.GetFolder
Find out the name of a folder's parent folder FileSystemObject.GetParentFolderName
Find out the path of system folders - FileSystemObject.GetSpecialFolder
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Working With Files
There are two major categories of
file manipulation
Creating, adding, or removing data,
and reading files.
Moving, copying, and deleting files.
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Creating Files
There are three ways to create an empty
text file.
The first way is to use the
CreateTextFile method.
The second way to create a text file is to
use the OpenTextFile method of the
FileSystemObject object with the
ForWriting flag set.
A third way to create a text file is to use
the OpenAsTextStream method with
the ForWriting flag set.
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Adding Data to the File
Once the text file is created, add data to the file using the following
three steps:
Open the text file.
Write the data.
Close the file.
To open an existing file, use either the OpenTextFile method of the
FileSystemObject object or the OpenAsTextStream method of the
File object.
To write data to the open text file, use the Write, WriteLine, or
WriteBlankLines methods of the TextStream object according to
your task.
To close an open file, use the Close method of the TextStream
object.
Note The newline character contains a character or characters to
advance the cursor to the beginning of the next line. Be aware that
the end of some strings may already have such nonprinting
characters.
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Reading Files
To read data from a text file, use the
Read, ReadLine, or ReadAll method of
the TextStream object.
If you use the Read or ReadLine method
and want to skip to a particular portion of
data, use the Skip or SkipLine method.
The resulting text of the read methods is
stored in a string which can be displayed
in a control, parsed by string functions
(such as Left, Right, and Mid),
concatenated, and so forth.
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Moving, Copying, and Deleting
Files
The FSO object model has two
methods each for moving, copying,
and deleting files
Move a file - File.Move or
FileSystemObject.MoveFile
Copy a file - File.Copy or
FileSystemObject.CopyFile
Delete a file - File.Delete or
FileSystemObject.DeleteFile
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Lab 11.1
Tip
Const
Const
Const
Const
Const
Const
Dani Vainstein
DRV_UNKNOWN = 0
DRV_REMOVABLE = 1
DRV_FIXED = 2
DRV_NETWORK = 3
DRV_CDROM = 4
DRV_RAMDISK = 5
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Lab 11.2
Declare the follow constants :
Constants returned by Drive.DriveType
Const
Const
Const
Const
Const
conDriveTypeRemovable = 1
conDriveTypeFixed = 2
conDriveTypeNetwork = 3
conDriveTypeCDROM = 4
conDriveTypeRAMDisk = 5
Const
Const
Const
Const
Const
Const
Const
Const
Const
conFileAttrNormal = 0
conFileAttrReadOnly = 1
conFileAttrHidden = 2
conFileAttrSystem = 4
conFileAttrVolume = 8
conFileAttrDirectory = 16
conFileAttrArchive = 32
conFileAttrAlias = 64
conFileAttrCompressed = 128
Constants returned by File.Attributes
Constants for opening files
Const conOpenFileForReading = 1
Const conOpenFileForWriting = 2
Const conOpenFileForAppending = 8
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Lab 11.2
Write the following functions.
ShowDriveType(objDrive) - Generates a string describing the
drive type of a given Drive object.
ShowFileAttr(objFile) - Generates a string describing the
attributes of a file or folder.
GenerateDriveInformation(objFSO) – reports about the Drive
Letter,Path, Type, IsReady, ShareName, VolumeName, TotalSize,
FreeSpace, AvailableSpace, and SerialNumber.
GenerateFileInformation(objFile) – File Name, Type, File
Attributes, Date Created, Last Accessed, Last Modified and Size
GenerateFolderInformation(objFolder) – Folder Name, Folder
Attributes, Date Created, Last Accessed, Last Modified and Size
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Lab 11.1
Create a Folder in the D:\ drive, if not exist in
C:\ Drive.
The name of the folder is VBSInfo.
Create a file in the folder, TestInfo.txt
The file will contain the report of the program.
The data will displayed like a table (rows and
columns with headers) use the vbTab for
separate the data.
For getting information about the directories
and files, please DON’T do it an all drives, select
only the drive were you created your file.
Dani Vainstein
60
Lab 11.1
Create a Folder in the D:\ drive, if not exist in
C:\ Drive.
The name of the folder is VBSInfo.
Create a file in the folder, TestInfo.txt
The file will contain the report of the program.
The data will displayed like a table (rows and
columns with headers) use the vbTab for
separate the data.
For getting information about the directories
and files, please DON’T do it an all drives, select
only the drive were you created your file.
Dani Vainstein
61
What’s Next
What means error handling.
When to use On Error statements.
Using the error object.
Raising our own errors.
The next session is for advanced users.
Dani Vainstein
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Make sure to visit us
Tutorials
Articles
Proikects
And much more
www.AdvancedQTP.com
63
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