[DefaultMember("Item")]
public class WorksheetCollection : WorkbookElement 

using( var doc = Workbook.Load( "test.xlsx") )   // Loads an existing Workbook named “test.xlsx”.
  {
    var worksheetA = doc.Worksheets[ 1 ];         // Gets the second worksheet. 
    var worksheetB = doc.Worksheets[ “Sheet3” ];         // Gets the worksheet named “Sheet3”. 
    doc.Worksheets.Add();                                   // Adds a new Worksheet.
    doc.Worksheets.Add( "ThirdSheet" );         // Adds a new Worksheet with a specific name.
    if( doc.Worksheets.Contains( "ThirdSheet" ) ) // Looks for a specific Worksheet.
      {
        Debug.WriteLine( "Found" );
      }
    doc.Save(); 
  }