[excel] How do I create an Excel chart that pulls data from multiple sheets?

I have monthly sales figures stored in separate sheets. I would like to create a plot of sales for multiple products per month. Each product would be represented in a different colored line on the same chart with each month running along the x axis.

What is the best way to create a single line chart that pulls from the same relative cells on multiple sheets?

Here's some code from Excel 2010 that may work. It has a couple specifics (like filtering bad-encode characters from titles) but it was designed to create multiple multi-series graphs from 4-dimensional data having both absolute and percentage-based data. Modify it how you like:

Sub createAllGraphs()

Const chartWidth As Integer = 260
Const chartHeight As Integer = 200




If Sheets.Count = 1 Then
    Sheets.Add , Sheets(1)
    Sheets(2).Name = "AllCharts"
ElseIf Sheets("AllCharts").ChartObjects.Count > 0 Then
    Sheets("AllCharts").ChartObjects.Delete
End If
Dim c As Variant
Dim c2 As Variant
Dim cs As Object
Set cs = Sheets("AllCharts")
Dim s As Object
Set s = Sheets(1)

Dim i As Integer


Dim chartX As Integer
Dim chartY As Integer

Dim r As Integer
r = 2

Dim curA As String
curA = s.Range("A" & r)
Dim curB As String
Dim curC As String
Dim startR As Integer
startR = 2

Dim lastTime As Boolean
lastTime = False

Do While s.Range("A" & r) <> ""

    If curC <> s.Range("C" & r) Then

        If r <> 2 Then
seriesAdd:
            c.SeriesCollection.Add s.Range("D" & startR & ":E" & (r - 1)), , False, True
            c.SeriesCollection(c.SeriesCollection.Count).Name = Replace(s.Range("C" & startR), "Â", "")
            c.SeriesCollection(c.SeriesCollection.Count).XValues = "='" & s.Name & "'!$D$" & startR & ":$D$" & (r - 1)
            c.SeriesCollection(c.SeriesCollection.Count).Values = "='" & s.Name & "'!$E$" & startR & ":$E$" & (r - 1)
            c.SeriesCollection(c.SeriesCollection.Count).HasErrorBars = True
            c.SeriesCollection(c.SeriesCollection.Count).ErrorBars.Select
            c.SeriesCollection(c.SeriesCollection.Count).ErrorBar Direction:=xlY, Include:=xlBoth, Type:=xlCustom, Amount:="='" & s.Name & "'!$F$" & startR & ":$F$" & (r - 1), minusvalues:="='" & s.Name & "'!$F$" & startR & ":$F$" & (r - 1)
            c.SeriesCollection(c.SeriesCollection.Count).ErrorBar Direction:=xlX, Include:=xlBoth, Type:=xlFixedValue, Amount:=0

            c2.SeriesCollection.Add s.Range("D" & startR & ":D" & (r - 1) & ",G" & startR & ":G" & (r - 1)), , False, True
            c2.SeriesCollection(c2.SeriesCollection.Count).Name = Replace(s.Range("C" & startR), "Â", "")
            c2.SeriesCollection(c2.SeriesCollection.Count).XValues = "='" & s.Name & "'!$D$" & startR & ":$D$" & (r - 1)
            c2.SeriesCollection(c2.SeriesCollection.Count).Values = "='" & s.Name & "'!$G$" & startR & ":$G$" & (r - 1)
            c2.SeriesCollection(c2.SeriesCollection.Count).HasErrorBars = True
            c2.SeriesCollection(c2.SeriesCollection.Count).ErrorBars.Select
            c2.SeriesCollection(c2.SeriesCollection.Count).ErrorBar Direction:=xlY, Include:=xlBoth, Type:=xlCustom, Amount:="='" & s.Name & "'!$H$" & startR & ":$H$" & (r - 1), minusvalues:="='" & s.Name & "'!$H$" & startR & ":$H$" & (r - 1)
            c2.SeriesCollection(c2.SeriesCollection.Count).ErrorBar Direction:=xlX, Include:=xlBoth, Type:=xlFixedValue, Amount:=0
            If lastTime = True Then GoTo postLoop
        End If

        If curB <> s.Range("B" & r).Value Then

            If curA <> s.Range("A" & r).Value Then
                chartX = chartX + chartWidth * 2
                chartY = 0
                curA = s.Range("A" & r)
            End If

            Set c = cs.ChartObjects.Add(chartX, chartY, chartWidth, chartHeight)
            Set c = c.Chart
            c.ChartWizard , xlXYScatterSmooth, , , , , True, Replace(s.Range("B" & r), "Â", "") & " " & s.Range("A" & r), s.Range("D1"), s.Range("E1")

            Set c2 = cs.ChartObjects.Add(chartX + chartWidth, chartY, chartWidth, chartHeight)
            Set c2 = c2.Chart
            c2.ChartWizard , xlXYScatterSmooth, , , , , True, Replace(s.Range("B" & r), "Â", "") & " " & s.Range("A" & r) & " (%)", s.Range("D1"), s.Range("G1")

            chartY = chartY + chartHeight
            curB = s.Range("B" & r)
            curC = s.Range("C" & r)
        End If

        curC = s.Range("C" & r)
        startR = r
    End If

    If s.Range("A" & r) <> "" Then oneMoreTime = False ' end the loop for real this time
    r = r + 1
Loop

lastTime = True
GoTo seriesAdd
postLoop:
cs.Activate

End Sub

2007 is more powerful with ribbon..:=) To add new series in chart do: Select Chart, then click Design in Chart Tools on the ribbon, On the Design ribbon, select "Select Data" in Data Group, Then you will see the button for Add to add new series.

Hope that will help.