How to Write An Array To An Excel Worksheet in c# interoperability

You can use Free Spire.XLS library to insert array into an Excel worksheet. 

Here is a basic example:

using Spire.Xls;
namespace SetArrayofValues
{
    class Program
    {
            private void SetArrayValueExample()
        {
            Workbook workbook = new Workbook();
            workbook.CreateEmptySheets(1);

            Worksheet sheet = workbook.Worksheets[0];

            int maxRow = 10000;
            //int maxRow = 5;
            int maxCol = 200;

            //int maxCol = 5;
            object[,] myarray = new object[maxRow + 1, maxCol + 1];
            bool[,] isred = new bool[maxRow + 1, maxCol + 1];
            for (int i = 0; i <= maxRow; i++)
                for (int j = 0; j <= maxCol; j++)
                {
                    myarray[i, j] = i + j;
                    if ((int)myarray[i, j] > 8)
                        isred[i, j] = true;
                }

            sheet.InsertArray(myarray, 1, 1);

            workbook.SaveToFile("test.xls",ExcelVersion.Version97to2003);
        }
    }
}

For more information, check this link:

https://www.e-iceblue.com/Tutorials/Spire.XLS/Spire.XLS-Program-Guide/Set-an-Array-of-Values-into-a-Range-in-Excel-Worksheet.html