Modeling using VBA

Modeling using VBA

Using Toolbox

This is a label

This is a button

Using the Toolbox select a GUI element and by mouse-click place it on the frame This is a text box

Using User Form Work with Common Button, Text Box

Using User Form Work with Common Button, Text Box

Working with Combo Box

Working with List Box

Working with Image Control, Spin Button

Work with Multipage, Option controls

Work with Scroll Bar, Check Box, Frame controls

Work with additional controls

Modules & Procedures

• Module – collection of logically related procedures & functions grouped together

• Procedure – a group of ordered statements enclosed by Sub and End Sub

• Function – the same as a procedure, but also returns some value and is enclosed between Function and End Function key words

Procedure & Function Examples

Sub ShowTime() Range("C1") = Now()

End Sub

Function sumNo(x, y)     sumNo = x + y

End FunctionFunction: returns something

Procedure: doesn’ t returns anything

Calling procedures vs. calling functions

Sub z(a)    MsgBox a

End Sub

Sub x()    Call z("ABC")

End Sub

Sub y()    z "ABC“

End Sub

Sub ShowSum()varSum=  Module1.sumNo(3,5)

MsgBox varSumEnd Sub

Function sumNo(x, y)     sumNo = x + y

End Function

If there are several sumNo functions in several modules/forms, need to use the full name of the function

Passing Arguments by Value or by Reference

• Passing arguments by reference – – Is the VBA default– Means, if any changes happened to the argument

variables, they will be preserved after the function/procedure finishes

• Passing arguments by value –– Is possible in VBA (by explicit definition)– Means, the pre-calling state of the argument variables will

be preserved after the procedure/function finishes

Arguments by Ref/by Val. Examples

Sub TestPassing1()    Dim y As Integer    y = 50    AddNo1 y    MsgBox y AddNo2 y MsgBox y

End Sub

Sub AddNo1(ByRef x As Integer)    x = x + 10

End Sub

Sub AddNo2(x As Integer)x = x + 10

End Sub

public Sub TestPassing2()    Dim y As Integer    y = 50    AddNo3 y    MsgBox y

End Sub

private Sub AddNo3(ByVal x _ As Integer)    x = x + 10

End Sub

Functions/Procedure Scope

• Use public to allow any module to call the function/procedure

• Use private to make limited access to the function/procedure (only from the owning module)

VBA Variables

• A variable is used to store temporary information within a Procedure, Function, Module…

• A variable name– Must start with letter and can’t contain spaces and special

characters (such as “&”, “%”, “\”) – Can’t be any excel keyword (“if”, “while”…)– Can’t have identical name to any existing class

(“Worksheet”, “Workbook”…)

VBA Data Type

• Byte – positive integer numbers (0:255)• Integer – integers (-32,768 : 32,767)• Long – 4-byte integer• Currency – for fixed-point calculations• Single – 2-byte floating-point numbers• Double – double-precision floating-point numbers• Date – used to store dates and times as real

numbers.• String – contains a sequence of characters

Using Variables

• Declaring Variables– Format: Dim varibleName AS dataType– Examples:

• Dim myText As String • Dim myNum As Integer• Dim myObj As Range

– The default value of • any numeric variable is zero• any string variable – “” (empty string)• an Object variable – is nothing