Aspen Touch Solutions ATM-123R Series Specifikace stáhnout pdf (Strana 29)

Automation 2-15

2-15

necessary to subtract one in order to access all the objects in

the collection.

The example below, is identical to the first example except that

a For Each loop is used instead of the standard For loop in order

to enumerate through the Streams collection.

Variants

A property can return a variety of variable types. Values such as

temperature and pressure are returned as doubles or 32-bit

floating-point values. The stream name property returns a string

value. Visual Basic provides an additional variable called a

variant. A variant is a variable that can take on the form of any

type of variable including, Integers, Double, String, Array, and

Objects.

If the property of an object returns an array whose size can vary

depending upon the case, then a variant is used to access that

value. For example, the ComponentMassFractionValue property

of a ProcessStream returns an array of doubles sized to the

number of components associated with that stream.

In Visual Basic, if a variable is not explicitly declared then it is

Example 1: Accessing Collection Objects

Dim hyStreams As Streams

Dim hyStream As ProcessStream

Set hyStreams = hyCase.Flowsheet.MaterialStreams

For j = 0 To hyStreams.Count - 1

MsgBox hyStreams.Item(j).name

Next j

Example 2: Accessing Collection Objects

Dim hyStreams As Streams

Dim hyStream As ProcessStream

Set hyStreams = hyCase.Flowsheet.MaterialStreams

For Each hyStream In hyStreams

MsgBox hyStream.name

Next hyStream

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Aspen Touch Solutions ATM-123R Series Specifikace Strana 29