object representing a diagram.
expression.Diagram
expression Required. An expression that returns one of the objects in the Applies To list.
Example
In this example, an organization chart diagram is added to the active worksheet. Microsoft Excel then displays a message with the number of nodes added to the diagram.
Sub UseDiagram()
Dim wksOne As Worksheet
Dim shpOrgChart As Shape
Set wksOne = ActiveSheet
'Add organization chart diagram to current worksheet.
Set shpOrgChart = ActiveSheet.Shapes.AddDiagram _
(Type:=msoDiagramOrgChart, _
Top:=10, Left:=15, Width:=400, Height:=475)
'Add first node to organization chart.
shpOrgChart.DiagramNode.Children.AddNode
'Notify user of the number of nodes added to the diagram.
MsgBox shpOrgChart.Diagram.Nodes.Count
End Sub