In large projects, creating sequence diagrams manually for thousands of messages can be time-consuming and error-prone. This article discusses how to automate the process of creating sequence diagrams in Visio using Excel data. We will cover the key concepts related to this process, including the creation of data sources in Excel, the use of Visio's ShapeSheet to define custom behaviors, and the application of Visual Basic for Applications (VBA) to automate the diagram creation process.
Creating Data Sources in Excel
To create a data source for a sequence diagram, you need to organize the data in a table format with columns for each element of the sequence diagram, such as lifelines, messages, and return values. Each row in the table should represent a single message, and the data source should be sorted by the order in which the messages appear in the sequence diagram.
For example, the following table shows a data source for a sequence diagram that describes a simple order processing system:
Lifeline
Message
Return Value
Sequence
Customer
Place Order
Order ID
1
Order Processor
Receive Order
2
Order Processor
Process Order
3
Order Processor
Calculate Shipping Cost
4
Order Processor
Calculate Tax
5
Order Processor
Charge Customer
Total Cost
6
Defining Custom Behaviors in Visio's ShapeSheet
Visio allows you to define custom behaviors for shapes through its ShapeSheet. By using the ShapeSheet, you can specify formulas that control the appearance and behavior of shapes, such as the position, size, and color of a shape. This functionality is particularly useful for creating custom shapes for sequence diagrams, such as lifelines and message shapes.
For example, the following formula in the ShapeSheet sets the position of a message shape based on the sequence number:
PinX = User.Sequence * (Width/2)
Automating Visio with Visual Basic for Applications
Visio includes a powerful programming environment called Visual Basic for Applications (VBA), which allows you to automate repetitive tasks and integrate Visio with other applications, such as Excel. By using VBA, you can create a macro that reads data from an Excel data source and creates a sequence diagram in Visio based on that data.
The following code block shows a VBA macro that creates a sequence diagram using the data source from earlier:
Sub CreateSequenceDiagram()
Dim appVisio As Visio.Application
Set appVisio = CreateObject("Visio.Application")
' Open the Visio document
Dim docVisio As Visio.Document
Set docVisio = appVisio.Documents.OpenEx("SequenceDiagram.vss")
' Add a new page
Dim pageVisio As Visio.Page
Set pageVisio = docVisio.Pages.Add
' Create a master for the lifeline shape
Dim masLifeline As Visio.Master
Set masLifeline = docVisio.Masters.Add("LifelineMaster.vss", visImportMasterSilent)
' Create a master for the message shape
Dim masMessage As Visio.Master
Set masMessage = docVisio.Masters.Add("MessageMaster.vss", visImportMasterSilent)
' Read the data from Excel
Dim wbExcel As Excel.Workbook
Set wbExcel = Excel.Application.Workbooks.Open("Data.xlsx")
Dim wsExcel As Excel.Worksheet
Set wsExcel = wbExcel.Worksheets("Sheet1")
Dim rngData As Excel.Range
Set rngData = wsExcel.Range("A1:D8")
' Loop through the data rows
Dim iRow As Long
For iRow = 1 To rngData.Rows.Count
Dim lifeline As Visio.Shape
Set lifeline = pageVisio.Drop(masLifeline, 0, 0)
lifeline.Text = rngData.Cells(iRow, 1)
Dim message As Visio.Shape
Set message = pageVisio.Drop(masMessage, lifeline.PinX, lifeline.PinY + (iRow - 1) * (lifeline.Height + 1))
message.Text = rngData.Cells(iRow, 2)
If rngData.Cells(iRow, 3).Value <> "" Then
message.Text += " [" + rngData.Cells(iRow, 3).Value + "]"
End If
Next iRow
' Save the Visio document
pageVisio.PageSheet.Cells("PageWidth").FormulaU = "16in"
pageVisio.PageSheet.Cells("PageHeight").FormulaU = "10in"
docVisio.SaveAs "SequenceDiagram.vsd"
End Sub
Automating the creation of sequence diagrams in Visio using Excel data can save time and reduce errors in large projects. By using data sources in Excel, custom behaviors in Visio's ShapeSheet, and automation with Visual Basic for Applications (VBA), you can create a sequence diagram for a large project in a fraction of the time it would take to create it manually. With this process, you can focus on the design and implementation of your project, rather than the tedious task of creating sequence diagrams.