Question

Is there an event that can detect when the active row count of an Excel Sheet increases by 1? If not, is there another way to do it?

Answer 1

Probably the closest thing is the SelectionChange event. You can get the Rows.Count property of the Target argument:

using Excel = Microsoft.Office.Interop.Excel;

private int rowsBefore = 0;

void SomeMethod() {
    Excel.Application app = new Excel.Application();
    Excel.Workbook wb = app.Workbooks.Add();
    Excel.Worksheet ws = (Excel.Worksheet)wb.Worksheets[0];
    ws.SelectionChange += new Excel.DocEvents_SelectionChangeEventHandler(ws_SelectionChange);
}

void ws_SelectionChange(Excel.Range Target) {
    int rowsNow = Target.Rows.Count;
    if (rowsNow > rowsBefore) {
        // do stuff
    }
    rowsBefore = rowsNow;
}