// C#
private void CreateChart()
{
    // Now create the chart.
    Excel.Chart xlChart = (Excel.Chart)ThisWorkbook.Charts.
        Add(Type.Missing, xlSheet, Type.Missing, Type.Missing);

    Excel.Range cellRange = (Excel.Range)xlSheet.Cells[1, 1];
    xlChart.ChartWizard(cellRange.CurrentRegion,
        Excel.Constants.xl3DBar, Type.Missing,
        Excel.XlRowCol.xlColumns, 1, 2, false,
        xlSheet.Name, Type.Missing, Type.Missing,
        Type.Missing);

    // Apply some formatting to the chart.
    xlChart.Name = xlSheet.Name + " Chart";

    Excel.ChartGroup grp = (Excel.ChartGroup)xlChart.ChartGroups(1);
    grp.GapWidth = 20;
    grp.VaryByCategories = true;
    xlChart.ChartTitle.Font.Size = 16;
    xlChart.ChartTitle.Shadow = true;
    xlChart.ChartTitle.Border.LineStyle = Excel.Constants.xlSolid;
}