public LoadFeatureSheetsViewModel()  
        {  
            Filter = "Excel Spreadsheets (.xlsx)|*.xlsx|All Files (*.*)|*.*";  
            FilterIndex = 1;  
            Sheet1Path = "C:PATH\\Fatigue Calculation Results.xlsx";  
            FileStream stream = new FileStream("C:PATH\\Fatigue Calculation Results.xlsx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite);  
            Sheet1Source = new SpreadsheetDocumentSource(stream, DocumentFormat.OpenXml);  
            Title = "Select Feature Sheet";  
        }