[]
Gets or sets the formula of the chart title using A1-style notation, in English.
string Formula { get; set; }
Property Formula As String
worksheet.Range["E1"].Value = "Sales Analysis";
IChart chart = worksheet.Shapes.AddChart(ChartType.ColumnClustered, 20, 20, 300, 200).Chart;
chart.HasTitle = true;
chart.ChartTitle.Formula = "=Sheet1!$E$1";
string formula = chart.ChartTitle.Formula;