GraphicItem.SetExpression Method

Sets the value of the expression string that is part of a GraphicItem object’s rule, against which shape data (custom properties) are evaluated.

Note
This Visio object or member is available only to licensed users of Microsoft Office Visio Professional 2007.

Version Information
 Version Added:  Visio 2007

Syntax

expression.SetExpression(Field, Expression)

expression   An expression that returns a GraphicItem object.

Parameters

Return Value
Nothing

Remarks

The Field parameter should be one of the following values from the VisGraphicField enumeration, which is declared in the Microsoft Office Visio Type Library.

When you pass the SetExpression method a shape-data-item label (that is, when you pass visGraphicPropertyLabel for the Field parameter), you must enclose the label within curly braces ({}). For example, if you want to pass the name of the "Cost" shape-data item, you must write it like this: {Cost}.

You can reference the shape data of a shape other than the one to which the data graphic is applied by passing the name of the shape followed by an exclamation point (!) and then the name of the field. For example, in the example shown below, to refer to the width of the shape named Ellipse.34, you could use the following syntax:

  vsoGraphicItem.SetExpression visGraphicExpression, "Ellipse.34!Width"

Before you can edit a graphic item, including setting its expression string, you must use the Master.Open method to open for editing a copy of the data graphic master whose GraphicItems collection the graphic item belongs to. After you have set the expression of the graphic item and made whatever other edits you want to make, use the Master.Close method to commit changes.

Example

The following Microsoft Visual Basic for Applications (VBA) macro shows how to use the SetExpression method to set the value of the expression string for a data graphic item. It opens a copy of the Master object of type visTypeDataGraphic (commonly called a data graphic) named "Data Graphic," and then sets the expression of the first graphic item in the GraphicItems collection of the data graphic to display the width of any shape to which the data graphic is applied.

Note
You can determine the name of an existing data graphic master by moving your mouse over the master in the Data Graphics task pane in the Visio user interface.

Then it closes the master and uses the GetExpression method to get the mostly recently applied expression for the graphic item. Finally, it prints the field type and the value of the expression in the Immediate window.

The macro assumes that a data graphic named "Data Graphic" exists in the current document. For more information about adding a data graphic master to the Masters collection of the current document, see Masters.AddEx.

  Public Sub SetExpression_Example()
Dim vsoMaster As Visio.Master
Dim vsoMasterCopy As Visio.Master
Dim vsoGraphicItem As Visio.GraphicItem
Dim strExpression As String
Dim fieldType As VisGraphicField

Set vsoMaster = Visio.ActiveDocument.Masters("Data Graphic")
Set vsoMasterCopy = vsoMaster.Open
Set vsoGraphicItem = vsoMasterCopy.GraphicItems(1)
  
vsoGraphicItem.SetExpression visGraphicExpression, "Width"
vsoMasterCopy.Close

vsoMaster.GraphicItems(1).GetExpression fieldType, strExpression

Debug.Print "Field type is "; fieldType
Debug.Print "Expression is "; strExpression

End Sub

See Also

• GraphicItem Object
• GraphicItem Object Members