How to find first and last cell in ExcelInterop and graph range in C#

Question

Trying to graph a simple csv file in Excel :

1,2,3
4,5,6
7,8,9

How do I programmatically determine the graphing range to be A1:C3?

I have tried

            var lastCell = worksheet.Cells.get_End(XlDirection.xlUp);

to determine the final column but it doesn't seem to work.

The following is the code that I am using to graph the file, and I just need to determine the range.

using Microsoft.Office.InteropServices.Excel;



        Application application = new Application();
        Workbook workbook = application.Workbooks.Open(fileName);
        var worksheet = workbook.Worksheets[1] as
            Microsoft.Office.Interop.Excel.Worksheet;


                   // Add chart.
        var charts = worksheet.ChartObjects() as
            Microsoft.Office.Interop.Excel.ChartObjects;
        var chartObject = charts.Add(60, 10, 300, 300) as
            Microsoft.Office.Interop.Excel.ChartObject;
        var chart = chartObject.Chart;

        // Set chart range.
        var range = worksheet.get_Range( ); //  ????????
        chart.SetSourceData(range);

        // Set chart properties.
        chart.ChartType = Microsoft.Office.Interop.Excel.XlChartType.xlLine;
        chart.ChartWizard(Source: range,
            Title: graphTitle,
            CategoryTitle: xAxis,
            ValueTitle: yAxis);


        // Save.
        workbook.Save();
        workbook.Close();

Answer 1

You can try to get your range in this way:

var range = worksheet.get_Range("A1", System.Type.Missing).CurrentRegion;

It gets the range which starts as of cell A1 until the last cell which make a range continuous area. I think this will be best option when working with CSV file.

According to MSDN (VBA):

(CurrentRegion) Returns a Range object that represents the current region. The current region is a range bounded by any combination of blank rows and blank columns.