How To VB3: Create Excel Chart with OLE Automation from VB (112417)

MORE INFORMATION

There are five key points you need to keep in mind when creating an Excel chart in a Visual Basic program:

1. A chart can be either on a Worksheet or a Chart sheet.
2. A chart on a Worksheet is a ChartObject.
3. A ChartObject has a Chart property, which is a Chart Object.
4. The data associated with the Chart is part of the SeriesCollection.
5. You can add a new data series with a Named Range.

NOTE: Complete definitions for these objects can be found in the Excel documentation.

A Workbook has a Charts collection, which is the collection of all Chart sheets in the workbook. All Charts on WorkSheets are part of that WorkSheet's ChartObjects collection. Therefore to add a new Chart to a Worksheet, you can use the Add method on the worksheet[ASCII 146]s ChartObject collection.

The SeriesCollection property of the Chart object contains the reference to the data linked to the table. In the example below, you'll add two data series -- each of which contains 10 data points -- by using the Add method on the SeriesCollection object.

Although the example passes the Range of cells containing the data as a named range, you could specify a Range in R1C1 notation.

Steps to Create Example Program

1. Start a new project in Visual Basic. Form1 is created by default.
2. Add a command button (Command1) to Form1.
3. Add the following code to the Command1_Click event procedure:

      Sub Command1_Click()
         Dim objXLsheet As Object ' Object reference to Excel Worksheet
         Dim objRange1 As Object  ' First series in the chart
         Dim objRange2 As Object  ' Second series in the chart
         Dim objChart1 As Object  ' Object reference to the chart we create
   
         Dim iRow As Integer ' Index variable for the current Row
         Dim iCol As Integer ' Index variable for the current Row
   
         Dim strTmpRange As String ' Temporarily hold Range in R1C1 notation
   
         Const cNumCols = 10 ' Number of points in each Series
         Const cNumRows = 2  ' Number of Series
   
         ' Create a Worksheet Object:
         Set objXLsheet = CreateObject("Excel.Sheet")
         Randomize Timer
   
         ' Insert Random data into Cells for the two Series:
         For iRow = 1 To cNumRows
            For iCol = 1 To cNumCols
               objXLsheet.Cells(iRow, iCol).Value = Int(Rnd * 50) + 1
            Next iCol
         Next iRow
   
         ' Insert Named Ranges:
         For iRow = 1 To cNumRows
            'VB3Line: Enter the following lines as one line
            strTmpRange = "R" & iRow & "C" & Format$(1) & ":R" & iRow &
               "C" & Format$(cNumCols)
            'VB3Line: Enter the following lines as one line
            objXLsheet.Parent.Names.Add "Range" & Format$(iRow),
               "=Sheet1!" & strTmpRange
         Next iRow
   
         ' Add a ChartObject to the worksheet:
         Set objChart1 = objXLsheet.ChartObjects.Add(100, 100, 200, 200)
   
         ' Assign the Ranges created above as the individual series
         ' for the chart:
         For iRow = 1 To cNumRows
            objChart1.Chart.SeriesCollection.Add "Range" & Format$(iRow)
         Next iRow
   
         ' Make Excel Visible:
         objXLsheet.application.Visible = True
         DoEvents
   
         ' Save the Worksheet to disk. The parent of a WorkSheet is WorkBook.
         objXLsheet.Parent.SaveAs "C:\VB\XLCHART.XLS"
   
         ' Close this instance of Excel:
         objXLsheet.application.Quit
      End Sub
   						

4. Press the F5 key to run the program, and click the command button.

At this point, Excel starts, and it loads and displays the worksheet with the newly-created chart. If you don't already have a file name as specified on the jXLSheet.Parent.SaveAs line of code, Excel saves the file and closes itself down. If you already have a file with the same name, Excel brings up a dialog asking you if you would like to overwrite the existing file.