C# Pie Chart SpreadsheetGear API Sample

Excel-Compatible Samples for .NET

Description

Creating Excel-compatible Pie Charts is trivial to do with SpreadsheetGear. At its most basic level you call IShapes.AddChart(...) and then set the returned chart object to use a ChartType.Pie chart type (or one of the other pie-based chart types).

The below sample demonstrates this process and performs a few other tasks to properly setup the chart:

Opens an Excel workbook (ChartData.xlsx) pre-populated with chart source data located in the Defined Name "TotalByQuarter" which points to the range L3:L6. This will be used to create a single series in the chart.
Charts are positioned on the worksheet relative to the top-left edge of the worksheet (in Points); however, you might want to position the column chart based on row / column indexes. SpreadsheetGear can take care of this conversion by using the IWorksheetWindowInfo.ColumnToPoints(double columnIndex) and RowToPoints(double rowIndex) methods.
Adds the chart at the specified worksheet location by calling IShapes.AddChart(double top, double left, double width, double height) and setting the source data for the chart by calling IChart.SetSourceData(IRange source, RowCol rowCol).
Sets the chart's type (IChart.ChartType) to ChartType.Pie. Other pie-based chart types are available, such as ChartType.PieExploded and others.
The single series in this piechart is accessed via IChart.SeriesCollection[...] to:
- Set the pie series labels (shown in the legend) via ISeries.XValues which are sourced from another Defined Name "Quarters" which points to the range G3:G6 and so will use the axis labels "Q1", "Q2", "Q3" and "Q4".
- Add data labels to each pie slice (ISeries.HasDataLabels = true), showing each data point's percentage (ISeries.DataLabels.ShowPercentage = true) and hiding the underlying data point's value (ISeries.DataLabels.ShowValue = false).
Adds a chart title by setting IChart.HasTitle to true, then sets the title text and other chart title options under the IChart.ChartTitle property.

Sample C# Source Code

// Open workbook with some data for the chart and get a reference to the active 
// sheet and its cells.
SpreadsheetGear.IWorkbook workbook = 
    SpreadsheetGear.Factory.GetWorkbook("ChartData.xlsx");
SpreadsheetGear.IWorksheet worksheet = workbook.ActiveWorksheet;
SpreadsheetGear.IRange cells = worksheet.Cells;

// Get a reference to the worksheet window info and shapes collection.
SpreadsheetGear.IWorksheetWindowInfo windowInfo = worksheet.WindowInfo;
SpreadsheetGear.Shapes.IShapes shapes = worksheet.Shapes;

// Add a chart to the worksheet's shape collection.
// NOTE: Calculate the coordinates of the chart by converting row and column
//       coordinates to points.  Use fractional row and column values to get 
//       coordinates anywhere in between row and column boundaries.
double left = windowInfo.ColumnToPoints(0.15);
double top = windowInfo.RowToPoints(0.5);
double right = windowInfo.ColumnToPoints(5.85);
double bottom = windowInfo.RowToPoints(13.5);
SpreadsheetGear.Charts.IChart chart =
    shapes.AddChart(left, top, right - left, bottom - top).Chart;

// Get the source data range from an existing defined name.
SpreadsheetGear.IRange source = workbook.Names["TotalByQuarter"].RefersToRange;

// Set the chart's source data range, plotting series in columns.
chart.SetSourceData(source, SpreadsheetGear.Charts.RowCol.Columns);

// Set the chart type to a pie chart.
chart.ChartType = SpreadsheetGear.Charts.ChartType.Pie;

// Get a reference to the single total series.
SpreadsheetGear.Charts.ISeries seriesTotal = chart.SeriesCollection[0];

// Add category labels by using an existing defined name.
seriesTotal.XValues = "=Quarters";

// Add series data labels and change to show percentage only.
seriesTotal.HasDataLabels = true;
seriesTotal.DataLabels.ShowPercentage = true;
seriesTotal.DataLabels.ShowValue = false;

// Add a chart title and change the font size.
chart.HasTitle = true;
chart.ChartTitle.Text = "Percentage of Sales by Quarter";
chart.ChartTitle.Font.Size = 12;