What is Dictionary Object - Overview

Dictionary object allows storing key value pairs. A dictionary object can be used for easy lookup of values. Dictionary is a not a QTP specific functionality and is available in normal VBScript as well.

Creating the Dictionary
A dictionary object can be created using CreateObject for COM class “Scripting.Dictionary”. The code below shows how to create the dictionary object in QTP


'Create the Dictionary Object
Set oDict = CreateObject("Scripting.Dictionary")


Below table shows list of methods that dictionary objects supports.
Method Description
Add (key, item)- Adds a key and item pair to a Dictionary object.
Exists(key)- Returns true if a specified key exists in the Dictionary object, false if it does not
Items() - Returns an array containing all the items in a Dictionary object
Keys() - Returns an array containing all existing keys in a Dictionary object.
Remove(key) - Removes a key, item pair from a Dictionary object
RemoveAll() - The RemoveAll method removes all key, item pairs from a Dictionary object.

Count - Returns the number of items in a Dictionary object. Read-only.
Item Sets or returns an item for a specified key in a Dictionary object. Read/write
Key(Key) Sets a key in a Dictionary object.

Adding Items to Dictionary:
There are two ways to Add items to dictionary. One is to use the Add method and another is to use the Item property. Both the methods are shown in code below
'Method 1 for Adding items to dictionary
'Add items to dictionary
oDict.Add "CA", "California"
oDict.Add "LA", "Los Angeles"

'The below line will throw an error as LA key already exist
oDict.Add "LA", "Los Angeles 2"

'Method 2 for adding items to dictionary
oDict.Item("CA") = "California"

'Item is the default property so ".Item" is not required
oDict("LA") = "Los Angeles"

'No Error this time as we are actually using the
'Item property and not the Add method
oDict("LA") = "Los Angeles 2"100 Miles From Memphis

Checklist for web services

Design Considerations

Design chunky interfaces to reduce round trips.

Prefer message-based programming over remote procedure call (RPC) style.

Use literal message encoding for parameter formatting.

Prefer primitive types for Web service parameters.

Avoid maintaining server state between calls.

Consider input validation for costly Web methods.

Consider your approach to caching.

Consider approaches for bulk data transfer and attachments.

Avoid calling local Web Services.
Connections
**********************************************************

Configure the maxconnection attribute.

Prioritize and allocate connections across discrete Web services.

Use a single identity for outbound calls.

Consider UnsafeAuthenticatedConnectionSharing with Windows Integrated Authentication.

Use PreAuthenticate with Basic authentication.
Threading
********************************************************************

Tune the thread pool using the formula for reducing contention.

Consider minIoThreads and minWorkerThreads for intermittent burst load.
One Way (Fire and Forget) Communication
**********************************************************************

Consider using the OneWay attribute if you do not require a response.
Asynchronous Web Methods
*********************************************************************

Use asynchronous Web methods for I/O operations.

Do not use asynchronous Web methods when you depend on worker threads.
Asynchronous Invocation
*********************************************************************

Consider calling Web services asynchronously when you have additional parallel work.

Use asynchronous invocation to call multiple unrelated Web services.

Call Web services asynchronously for UI responsiveness.
Timeouts
*********************************************************************

Set your proxy timeout appropriately.

Set your ASP.NET timeout greater than your Web service timeout.

Abort connections for ASP.NET pages that timeout before a Web services call completes.

Consider the responseDeadlockInterval attribute.
WebMethods
*********************************************************************

Prefer primitive parameter types.

Consider buffering.

Consider caching responses.

Enable session state only for Web methods that need it.
Serialization
*********************************************************************

Reduce serialization with XmlIgnore.

Reduce round trips.

Consider XML compression.
Caching
*********************************************************************

Consider output caching for less volatile data.

Consider providing cache-related information to clients.

Consider perimeter caching.
State Management
*********************************************************************

Use session state only where it is needed.

Avoid server affinity.
Attachments
*********************************************************************

Prefer Base64 encoding. Direct Internet Message Encapsulation (DIME) is a supported part of Web Services Enhancements (WSE), but Microsoft® is not investing in this approach long-term. DIME is limited because the attachments are outside the SOAP envelope.
COM Interop
*********************************************************************

Avoid single-threaded apartment (STA) COM objects.

VB Script - 3

Arrays

An array is a contiguous area in the memory referred to by a common name. It is a series of variables having the same data type. Arrays are used to store related data values. VBScript allows you to store a group of common values together in the same location. These values can be accessed with their reference numbers.

An array is made up of two parts, the array name and the array subscript. The subscript indicates the highest index value for the elements within the array. Each element of an array has a unique identifying index number by which it can be referenced. VBScript creates zero based arrays where the first element of the array has an index value of zero.

Declaring Arrays

An array must be declared before it can be used. Depending upon the accessibility, arrays are of two types:
• Local Arrays
A local array is available only within the function or procedure, where it is declared.

• Global Arrays
A global array is an array that can be used by all functions and procedures. It is declared at the beginning of the VBScript Code.

The Dim statement is used to declare arrays. The syntax for declaring an array is as follows:
Dim ArrayName(subscriptvalue)

Where, ArrayName is the unique name for the array and SubscriptValue is a numeric value that indicates the number of elements in the array dimension within the array.

Example:
Dim No_Passengers(3)
The No_Passengers can store 4 values.

Assigning values to the array
No_Passengers(0) = 1
No_Passengers(1) = 2
No_Passengers(2) = 3
No_Passengers(3) = 4

Static and Dynamic Arrays:

VBScript provides flexibility for declaring arrays as static or dynamic.
A static array has a specific number of elements. The size of a static array cannot be altered at run time.

A dynamic array can be resized at any time. Dynamic arrays are useful when size of the array cannot be determined. The array size can be changed at run time.
Next we will deal with user defined procedures, functions and subroutines.


This post is third in the VB Script and QTP series.

Here we shall talk about user defined procedures.

Procedures are set of executable statements.

In VBScript, there are two types of procedures:

Sub Procedures
Function Procedures




Sub Procedures

A sub procedure is a series of VBScript statements, enclosed by Sub and End Sub statements which perform actions but do not return a value. A sub procedure can take arguments. If a sub procedure doesn’t receive any arguments, its Sub statement must include an empty parenthesis().

The following Sub procedure uses two intrinsic, or built-in, VBScript functions, MsgBox and InputBox , to prompt a user for information. It then displays the results of a calculation based on that information. The calculation is performed in a Function procedure created using VBScript. The Function procedure is shown after the following discussion.

Sub ConvertTemp()
temp = InputBox("Please enter the temperature in degrees F.", 1)
MsgBox "The temperature is " & Celsius(temp) & " degrees C."
End Sub

Function Procedures

A function procedure is a series of VBScript statements enclosed by the Function and End Function statements. A function procedure is similar to a sub procedure but it can return value to the calling function. A function procedure can take arguments (constants, variables or expressions that are passed to it by a calling procedure). If a function procedure has no arguments, it Function statement must include an empty set of parenthesis. A function returns a value by assigning a value to its name in one or more statements of the procedure. Since VBScript has only one base data type, a function always returns a variant.

In the following example, the Celsius function calculates degrees Celsius from degrees Fahrenheit. When the function is called from the ConvertTemp Sub procedure, a variable containing the argument value is passed to the function. The result of the calculation is returned to the calling procedure and displayed in a message box.

Sub ConvertTemp()
temp = InputBox("Please enter the temperature in degrees F.", 1)
MsgBox "The temperature is " & Celsius(temp) & " degrees C."
End Sub

Function Celsius(fDegrees)
Celsius = (fDegrees - 32) * 5 / 9
End Function

Tips:
To get data out of a procedure, you must use a Function. Remember, a Function procedure can return a value; a Sub procedure can't.
AFunction in your code must always be used on the right side of a variable assignment or in an expression.
To call a Sub procedure from another procedure, type the name of the procedure along with values for any required arguments, each separated by a comma. The Call statement is not required, but if you do use it, you must enclose any arguments in parentheses.
The following example shows two calls to the MyProc procedure. One uses the Call statement in the code; the other doesn't. Both do exactly the same thing.

Call MyProc(firstarg, secondarg)

MyProc firstarg, secondarg

Notice that the parentheses are omitted in the call when the Call statement isn't used.

VB Script - 2

This is in continuation from VB Script and QTP - Part1 on our series of posts on VB Script. Here, we will dwell upon conditional constructs, iterative constructs and arrays.

Conditional Constructs

Conditional Constructs execute statements or repeat certain set of statements based on conditions.
The following conditional constructs are available in VBScript
• If – Then –Else
• Select Case

If – Then – Else Construct

The If – Then- Else Construct is used to evaluate whether a condition is true or false and depending on the result, to specify one or more statements to execute. Usually the condition is an expression that uses a comparison operator to compare one value or variable with another. The If- Then – Else statements can be nested to as many levels as needed.
For example:

Sub ReportValue(value)


If value = 0 Then
MsgBox value
ElseIf value = 1 Then
MsgBox value
ElseIf value = 2 then
Msgbox value
Else
Msgbox "Value out of range!"
End If

You can add as many ElseIf clauses as you need to provide alternative choices. Extensive use of the ElseIf clauses often becomes cumbersome. A better way to choose between several alternatives is the Select Case statement.

Select Case Construct

The Select-Case structure is an alternative to If Then Else for selectively executing one block of statements from among multiple blocks of statements. The Select Case Construct makes code more efficient and readable.

A Select Case structure works with a single test expression that is evaluated once, at the top of the structure. The result of the expression is then compared with the values for each Case in the structure. If there is a match, the block of statements associated with that Case is executed.

For example:
Select Case Document.Form1.CardType.Options(SelectedIndex).Text
Case "MasterCard"
DisplayMCLogo
ValidateMCAccount
Case "Visa"
DisplayVisaLogo
ValidateVisaAccount
Case "American Express"
DisplayAMEXCOLogo
ValidateAMEXCOAccount
Case Else DisplayUnknownImage PromptAgain
End Select
Iterative Constructs


Looping allows to run a group of statements repeatedly. The loop is repeated based on a condition. The loop runs as long as the condition is true. The following looping constructs are available in VBScript.
Do – Loop
While – Wend
For – Next

Do – Loop

Do – Loop statements are used to execute a block of statements based on a condition. The statements are repeated either while a condition is true or until a condition becomes true. While Keyword can be used to check a condition in a Do – Loop construct. The condition can be checked before entering into the loop or after the loop has run at least once.
The basic difference between a “Do while – Loop” and “Do - Loop while” is that the previous one gets executed only when the condition in the while statement holds true where as a “Do – Loop while” gets executed atleast once, because the condition in the while statement gets checked at the end of the first iteration.

While – Wend

The While...Wend statement is provided in VBScript for those who are familiar with its usage. However, because of the lack of flexibility in while...wend, it is recommended that you use Do...Loop instead.

For..Next

The For-Next loop can be used to run a block of statements a specific number of times. For loops use a counter variable whose value is increased or decreased with each repetition of the loop. The Step Keyword is used to increase or decrease the counter variable by the value that is specified along with it. The For-Next statement can be terminated before the counter reaches its end value by using the Exit For statement.
For example:
Dim j, total
For j = 2 To 10 Step 2
total = total + j
Next
MsgBox "The total is " & total