Exporting the values in List to excel

Using ClosedXML edit library( there is no need to install MS Excel

I just write a simple example to show you how you can name the file, the worksheet and select cells:

    var workbook = new XLWorkbook();
    workbook.AddWorksheet("sheetName");
    var ws = workbook.Worksheet("sheetName");

    int row = 1;
    foreach (object item in itemList)
    {
        ws.Cell("A" + row.ToString()).Value = item.ToString();
        row++;
    }

    workbook.SaveAs("yourExcel.xlsx");

If you prefer you can create a System.Data.DataSet or a System.Data.DataTable with all data and then just add it as a workseet with workbook.AddWorksheet(yourDataset) or workbook.AddWorksheet(yourDataTable);

Using the CSV idea, if it's just a list of Strings. Assuming l is your list:

using System.IO;

using(StreamWriter sw = File.CreateText("list.csv"))
{
  for(int i = 0; i < l.Count; i++)
  {
    sw.WriteLine(l[i]);
  }
}

OK, here is a step-by-step guide if you want to use COM.

1. You have to have Excel installed.
2. Add a reference to your project to the excel interop dll. To do this on the .NET tab select Microsoft.Office.Interop.Excel. There could be multiple assemblies with this name. Select the appropriate for your Visual Studio AND Excel version.
3. Here is a code sample to create a new Workbook and fill a column with the items from your list.

---

using NsExcel = Microsoft.Office.Interop.Excel;

public void ListToExcel(List<string> list)
{
    //start excel
    NsExcel.ApplicationClass excapp = new Microsoft.Office.Interop.Excel.ApplicationClass();

    //if you want to make excel visible           
    excapp.Visible = true;

    //create a blank workbook
    var workbook = excapp.Workbooks.Add(NsExcel.XlWBATemplate.xlWBATWorksheet);

    //or open one - this is no pleasant, but yue're probably interested in the first parameter
    string workbookPath = "C:\test.xls";
    var workbook = excapp.Workbooks.Open(workbookPath,
        0, false, 5, "", "", false, Excel.XlPlatform.xlWindows, "",
        true, false, 0, true, false, false);

    //Not done yet. You have to work on a specific sheet - note the cast
    //You may not have any sheets at all. Then you have to add one with NsExcel.Worksheet.Add()
    var sheet = (NsExcel.Worksheet)workbook.Sheets[1]; //indexing starts from 1

    //do something usefull: you select now an individual cell
    var range = sheet.get_Range("A1", "A1");
    range.Value2 = "test"; //Value2 is not a typo

    //now the list
    string cellName;
    int counter = 1;
    foreach (var item in list)
    {
        cellName = "A" + counter.ToString();
        var range = sheet.get_Range(cellName, cellName);
        range.Value2 = item.ToString();
        ++counter;
    }

    //you've probably got the point by now, so a detailed explanation about workbook.SaveAs and workbook.Close is not necessary
    //important: if you did not make excel visible terminating your application will terminate excel as well - I tested it
    //but if you did it - to be honest - I don't know how to close the main excel window - maybee somewhere around excapp.Windows or excapp.ActiveWindow
}