Thanks for considering Aspose APIs.
Please see the following sample code, its source and output Excel files as well as the screenshot for a reference.
source and output Excel files.zip (19.8 KB)
sc.png (53.5 KB)
//Open your sample Excel file
Workbook wb = new Workbook("sample.xlsx");
//Access first worksheet
Worksheet ws = wb.Worksheets;
//Access combo box, change its fill range and value property
Aspose.Cells.Drawing.ActiveXControls.ComboBoxActiveXControl combo = ws.Shapes.ActiveXControl as Aspose.Cells.Drawing.ActiveXControls.ComboBoxActiveXControl;
combo.ListFillRange = "J1:J4";
combo.Value = "Apple";
//Save the output Excel file