Using the following code I have created a single-cell bar graph (sort of a mutilation of the bar graph chart - for the record it's possible to do through the excel COM object).
int n = m_sheet.Charts.Add(ChartType.Bar, 0, 0, 1, 1);
Chart chart = m_sheet.Charts;
chart.NSeries.Add(CellsHelper.CellIndexToName(1, 1), true);
chart.NSeries[0].Line.Color = Color.Black;
chart.NSeries[0].Area.ForegroundColor = Color.Black;
chart.IsLegendShown = false;
chart.IsDataTableShown = false;
chart.PlotArea.X = 0;
chart.PlotArea.Y = 0;
chart.ChartArea.Border.Weight = 0;
chart.CategoryAxis.IsVisible = false;
chart.ValueAxis.IsVisible = false;
chart.ChartArea.Border.IsVisible = false;
chart.GapWidth = 0;
chart.MajorGridLines.IsVisible = false;
The neighboring cell houses the value, which is a percentage. The graph seems to work fine within a certain range, but is completely off outside of that range (seems to work for 50-50% up to about 95%)
Any ideas?