I have created an Open XML document file
in Existing Spreadsheet document open then read the 1st column value in this file.
- SpreadsheetDocument spreadsheetDocument =  
 -             SpreadsheetDocument.Open(srcFile, true);  
 -                 WorksheetPart newWorksheetPart = spreadsheetDocument.WorkbookPart.AddNewPart<WorksheetPart>();  
 -                 newWorksheetPart.Worksheet = new Worksheet(new SheetData());  
 -                 WorkbookPart workbookPart = spreadsheetDocument.WorkbookPart;  
 -                 Sheets sheets = spreadsheetDocument.WorkbookPart.Workbook.GetFirstChild<Sheets>();  
 -                 string relationshipId = spreadsheetDocument.WorkbookPart.GetIdOfPart(newWorksheetPart);  
 -                 uint sheetId = 1;  
 -                 
 -                 SheetData sheetData = newWorksheetPart.Worksheet.GetFirstChild<SheetData>();  
 -   
 -   
 -                 IEnumerable<WorksheetPart> worksheetPart = workbookPart.WorksheetParts;  
 -                 int rocount=0;  
 -                 Sheet sheet = workbookPart.Workbook.Descendants<Sheet>()  
 -                     .Where(s => s.Name == "Survey Details").FirstOrDefault();  
 -   
 -   
 -                 foreach (WorksheetPart WSP in worksheetPart)  
 -                 {  
 -                       
 -                     IEnumerable<SheetData> sheetData1 = WSP.Worksheet.Elements<SheetData>();  
 -                       
 -                     foreach (SheetData SD in sheetData1)  
 -                     {  
 -                         IEnumerable<Row> row = SD.Elements<Row>();   
 -                         IEnumerable<Column> column = SD.Elements<Column>();  
 -                         var d = column.Count();  
 -                         rocount=(row.Count());   
 -                     }  
 -                 }  
 
   how to read column value in c#