Activate a Worksheet

Updated on Jun 16, 2026

Typically, a single workbook in the document model contains several worksheets. However, only one worksheet can be active at a time. When you open a workbook through a spreadsheet UI, the control visualizes the cells of the active worksheet. Any changes you make through the UI, such as data entry or formatting, affect the active worksheet.

Changing the Active Worksheet

The Workbook class exposes an ActiveWorksheet property that gets and sets the active worksheet. Additionally, the workbook has an ActiveSheetChanged event that fires whenever the ActiveWorksheet changes. The first worksheet added to the workbook becomes the active worksheet by default. Each worksheet added afterwards does not become the active one.

Example 1 creates a new workbook from scratch and subscribes to its ActiveSheetChanged event. Further, the code adds two worksheets. When the first worksheet is added, it is automatically selected as the active worksheet because it is the only worksheet in the workbook. Adding the first worksheet also fires the ActiveSheetChanged event. When the second worksheet is added, the active worksheet does not change. The event does not fire. Later, the snippet sets the second worksheet to be the active one, which fires the ActiveSheetChanged event.

Example 1: Change Active Sheet

C#

public void ActivateWorksheetDemo()
{
	Workbook workbook = new Workbook();

	workbook.ActiveSheetChanged += this.Workbook_ActiveSheetChanged;

	workbook.Worksheets.Add();
	workbook.Worksheets.Add();

	workbook.ActiveWorksheet = workbook.Worksheets[1];
}

private void Workbook_ActiveSheetChanged(object sender, EventArgs e)
{
	//the active worksheet is changed
}