How to create an Excel WorkBook, Sheet in C#.NET

Recently, I had a requirement to export List to an Excel document separated by multiple sheets. I tried creating a .xlsx file using File.Create(filepath); approach which caused issues in writing into different sheets and workbook. So, I had to use interop library to get it done as follows. step 1: install interop nugget package to your solution

Microsoft.Office.Interop.Excel

step 2: Create a workbook and sheets

  
   var excel = new Microsoft.Office.Interop.Excel.Application(); 
   excel.Visible = false; 
   excel.DisplayAlerts = false; 
   var xlWorkBook = excel.Workbooks.Add(Type.Missing); 
   
   var xlSheets = xlWorkBook.Sheets as Microsoft.Office.Interop.Excel.Sheets;

   var worKsheeT =(Microsoft.Office.Interop.Excel.Worksheet)xlWorkBook.ActiveSheet; 
   worKsheeT.Name = "FirstSheet";
   
   var secondSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlSheets.Add(
    Type.Missing,Type.Missing, Type.Missing, Type.Missing); 
   secondSheet.Name = "SecondSheet";
              
    xlWorkBook.SaveAs(filePath);
    xlWorkBook.Close(); 
    excel.Quit();

  

How to KILL running excel processes in C#

While working with Excel files, you enconter multiple instance of excel processes are running in background(can be seen in Task Manger Processes). This will cause issues when trying to create and manupulate excel files in another program. Therefore, before working(reading/writing) with any excel objects, as a practice clean up the existing/running excel instances.

var processes = from p in Process.GetProcessesByName("EXCEL") select p;
            
foreach (var process in processes)
{
	process.Kill();
}