How can I add labels onto the pie pieces that are large enough to contain them, and alongside those that aren't?

Question

I've got simple bogus data that generates this Excel Chart:

This is the code:

object misValue = System.Reflection.Missing.Value;
//add data 
_xlSheet.Cells[11, 11] = "";
_xlSheet.Cells[11, 12] = "Student1";
_xlSheet.Cells[11, 13] = "Student2";
_xlSheet.Cells[11, 14] = "Student3";

_xlSheet.Cells[12, 11] = "Term1";
_xlSheet.Cells[12, 12] = "80";
_xlSheet.Cells[12, 13] = "65";
_xlSheet.Cells[12, 14] = "45";

_xlSheet.Cells[13, 11] = "Term2";
_xlSheet.Cells[13, 12] = "78";
_xlSheet.Cells[13, 13] = "72";
_xlSheet.Cells[13, 14] = "60";

_xlSheet.Cells[14, 11] = "Term3";
_xlSheet.Cells[14, 12] = "82";
_xlSheet.Cells[14, 13] = "80";
_xlSheet.Cells[14, 14] = "65";

_xlSheet.Cells[15, 11] = "Term4";
_xlSheet.Cells[15, 12] = "75";
_xlSheet.Cells[15, 13] = "82";
_xlSheet.Cells[15, 14] = "68";

Excel.Range chartRange;

Excel.ChartObjects xlCharts = (Excel.ChartObjects)_xlSheet.ChartObjects(Type.Missing);
Excel.ChartObject myChart = (Excel.ChartObject)xlCharts.Add(468, 160, 348, 268); //10, 80, 300, 250);
Excel.Chart chartPage = myChart.Chart;

chartRange = _xlSheet.get_Range("K11", "O15");
chartPage.SetSourceData(chartRange, misValue);
chartPage.ChartType = Excel.XlChartType.xlPieExploded; // xl3DPie; xlPie; xlColumnClustered;

What do I need to do to add labels onto the pie pieces that are large enough to contains them, and labels alongside those that aren't, with arrows pointing to the appropriate pie piece?

Answer 1

Adding labels is as easy as this:

chart.ApplyDataLabels(Excel.XlDataLabelsType.xlDataLabelsShowPercent, Excel.XlDataLabelsType.xlDataLabelsShowLabel, true, false, false, true, false, true);

In context:

object misValue = System.Reflection.Missing.Value;

_xlSheet.Cells[12, 11] = "John";
_xlSheet.Cells[12, 12] = "80";
_xlSheet.Cells[12, 13] = "165";
_xlSheet.Cells[12, 14] = "45";

_xlSheet.Cells[13, 11] = "Paul";
_xlSheet.Cells[13, 12] = "78";
_xlSheet.Cells[13, 13] = "72";
_xlSheet.Cells[13, 14] = "6";

_xlSheet.Cells[14, 11] = "George";
_xlSheet.Cells[14, 12] = "182";
_xlSheet.Cells[14, 13] = "180";
_xlSheet.Cells[14, 14] = "165";

_xlSheet.Cells[15, 11] = "Ringo";
_xlSheet.Cells[15, 12] = "7";
_xlSheet.Cells[15, 13] = "8";
_xlSheet.Cells[15, 14] = "6";

Excel.Range chartRange;

Excel.ChartObjects xlCharts = 
(Excel.ChartObjects)_xlSheet.ChartObjects(Type.Missing);
Excel.ChartObject chartObj = (Excel.ChartObject)xlCharts.Add(468, 160, 348, 268);
Excel.Chart chart = chartObj.Chart;

chartRange = _xlSheet.Range[_xlSheet.Cells[12, 11], _xlSheet.Cells[15, 14]];
chart.SetSourceData(chartRange, misValue);
chart.ChartType = Excel.XlChartType.xlPieExploded; 
chart.ApplyDataLabels(Excel.XlDataLabelsType.xlDataLabelsShowPercent, 
Excel.XlDataLabelsType.xlDataLabelsShowLabel, true, false, false, true, false, true);

It produces this exquisitely appointed graphic worthy of a disciple of Picasso: