How generate chart from Excel sheet using c# inter

I can generate excel file when i pass datatable into below function.

public static void ExportDataTableToExcel(DataTable dt, string filepath)
{

    object missing = Type.Missing;

    object misValue = System.Reflection.Missing.Value;

    //create excel
    Microsoft.Office.Interop.Excel.Application excel = new Microsoft.Office.Interop.Excel.Application();

    //add excel workbook
    Microsoft.Office.Interop.Excel.Workbook wb = excel.Workbooks.Add();

    //add worksheet to workbook
    Microsoft.Office.Interop.Excel.Worksheet ws = wb.Sheets[1] as Microsoft.Office.Interop.Excel.Worksheet;

    //add 2nd worksheet to workbook
    Microsoft.Office.Interop.Excel.Worksheet ws2 = wb.Sheets[2] as Microsoft.Office.Interop.Excel.Worksheet;

    //Set the header-row bold
    ws.Range["A1", "A1"].EntireRow.Font.Bold = true;

    //Adjust all columns
    ws.Columns.AutoFit();

   //spit top row
    ws.Application.ActiveWindow.SplitRow = 1;

    //insert image into worsheet 2
    ws2.Shapes.AddPicture("C:\\Koala.JPG", Microsoft.Office.Core.MsoTriState.msoFalse, Microsoft.Office.Core.MsoTriState.msoCTrue, 50, 50, 300, 300); 

    //freeze top row
    ws.Application.ActiveWindow.FreezePanes = true;


    int rowCount = 1;

    foreach (DataRow dr in dt.Rows)
    {

        rowCount += 1;

        for (int i = 1; i < dt.Columns.Count + 1; i++)
        {

            // Add the header the first time through

            if (rowCount == 2)
            {

                ws.Cells[1, i] = dt.Columns[i - 1].ColumnName;
                ws.Cells[1, i].Interior.ColorIndex = 40;

                // add cell border
                ws.Cells[1, i].Borders.LineStyle = Excel.XlLineStyle.xlContinuous;

            }

            ws.Cells[rowCount, i] = dr[i - 1].ToString();

            // add cell border
            ws.Cells[rowCount, i].Borders.LineStyle = Excel.XlLineStyle.xlContinuous;

        }

    }

    Microsoft.Office.Interop.Excel.Range range = (Microsoft.Office.Interop.Excel.Range)ws.UsedRange;

    Console.Write(range.ToString());


    wb.SaveAs(@"C:\Test.xls", Excel.XlFileFormat.xlWorkbookNormal, misValue,
                                         misValue, misValue, misValue,
                                         Excel.XlSaveAsAccessMode.xlExclusive, misValue,
                                         misValue, misValue, misValue, misValue);

    wb.Close(missing, missing, missing);

    excel.Quit();
}

This function works well . I need to add a graph from C# code to this excel file. I tried few methods.But did not find proper way to implement. Guys can you help me ?

Take a look at the tutorial here (one of the first Google hits).

It very clearly describe how to make a simple chart in Excel from C# code.

The general idea is like this:

// 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(topLeft, bottomRight);
chart.SetSourceData(range);

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