Chart axes in PowerPoint file

Question

I'm creating a chart (of ComboChart type) in the PPTX file using GemBox.Presentation (together with GemBox.Spreadsheet). I'm using the code from the PowerPoint Chart example and added parts of the Excel Combo Chart example.

This is what I have so far:

var presentation = new PresentationDocument();
var slide = presentation.Slides.AddNew(SlideLayoutType.Custom);
var chart = slide.Content.AddChart(GemBox.Presentation.ChartType.Combo, 25, 25, 300, 500);
var comboChart = (ComboChart)chart.ExcelChart;
var worksheet = comboChart.Worksheet;

worksheet.Cells["A1"].Value = "Name";
worksheet.Cells["A2"].Value = "John Doe";
worksheet.Cells["A3"].Value = "Fred Nurk";

worksheet.Cells["B1"].Value = "Salary";
worksheet.Cells["B2"].Value = 4023;
worksheet.Cells["B3"].Value = 3263;

worksheet.Cells["C1"].Value = "Max";
worksheet.Cells["C2"].Value = 4500;
worksheet.Cells["C3"].Value = 4300;

worksheet.Cells["D1"].Value = "Min";
worksheet.Cells["D2"].Value = 3000;
worksheet.Cells["D3"].Value = 2800;

comboChart.CategoryLabelsReference = "A2:A3";

var salaryChart = comboChart.Add(GemBox.Spreadsheet.Charts.ChartType.Column);
salaryChart.Series.Add("=B1", "B2:B3");

var minMaxChart = comboChart.Add(GemBox.Spreadsheet.Charts.ChartType.Line);
minMaxChart.Series.Add("=C1", "C2:C3");
minMaxChart.Series.Add("=D1", "D2:D3");

presentation.Save("output.pptx");

And this is what I get:

Now my problem is that I cannot find any way to access and format the Category axis and Vertical axis.

I tried to use chart, comboChart, salaryChart, and minMaxChart objects, but none of them have any axes properties!?

How can I, let's say, set the axes titles?

Answer 1

To set the axes of the Combo chart, you'll need to use the axes of one of its containing charts, so either salaryChart or minMaxChart.

Now the reason why you don't see any axes properties on them is that they are of a base type (ExcelChart). You need to cast them to a derived type, like this:

var salaryChart = (ColumnChart)comboChart.Add(GemBox.Spreadsheet.Charts.ChartType.Column);
salaryChart.Series.Add("=B1", "B2:B3");

salaryChart.Axes.Horizontal.Title.Text = "My Categories";
salaryChart.Axes.Vertical.Title.Text = "My Values";