using Application = Microsoft.Office.Interop.Excel.Application; namespace ExcelAddIn.Tools; public class Button2Tool : Tool { private readonly Application app; public Button2Tool() { app = (Application)ExcelDnaUtil.Application; } public override void Execute() { if (app.ActiveCell == null) { return; } double? cellValue = app.ActiveCell.Cells.Value2; if (cellValue != null) { app.ActiveCell.Cells.Value2 = ++cellValue; } } protected override void Dispose(bool disposing) { } }