Export DataGridView to Excel

public void ExportExcell(DataGridView dgw, int[] columnsToExport, int columnsWidth, string path, bool visible, bool quit)

        {

            Microsoft.Office.Interop.Excel.Application ExcelApp = new Microsoft.Office.Interop.Excel.Application();

            ExcelApp.Application.Workbooks.Add(Type.Missing);

            ExcelApp.Columns.ColumnWidth = columnsWidth;

            int columnExcel = 1;

            List<int> columns = new List<int>();

            for (int a = 0; a < (columnsToExport.Length); a++)

                columns.Add(columnsToExport[a]);

            for (int i = 0; i < dgw.Columns.Count; i++)

            {

                if (columns.Contains(i))

                {

                    ExcelApp.Cells[1, columnExcel] = dgw.Columns[i].HeaderText;

                    columnExcel++;

                }

            }

            columnExcel = 1;

            for (int i = 0; i < dgw.Rows.Count; i++)

            {

                for (int j = 0; j < dgw.Columns.Count; j++)

                {

                    if (columns.Contains(j))

                    {

                        ExcelApp.Cells[i + 2, columnExcel] = dgw.Rows[i].Cells[j].Value.ToString();

                        columnExcel++;

                    }

                    //+2 because must write from second row of the excel sheet

                }

                columnExcel = 1;

            }

            ExcelApp.Visible = visible;

            if (!String.IsNullOrEmpty(path))

            {

                ExcelApp.ActiveWorkbook.SaveCopyAs(path);

                ExcelApp.ActiveWorkbook.Saved = true;

            }

           

            if(quit)

                ExcelApp.Quit();

        }

public void ExportExcell(DataGridView dgw, string[] columnsToExport, int columnsWidth, string path, bool visible, bool quit)

        {

            Microsoft.Office.Interop.Excel.Application ExcelApp = new              Microsoft.Office.Interop.Excel.Application();

            ExcelApp.Application.Workbooks.Add(Type.Missing);

            ExcelApp.Columns.ColumnWidth = columnsWidth;

            int columnExcel = 1;

            List<string> columns = columnsToExport.OfType<string>().ToList();

            for (int i = 0; i < columnsToExport.Length; i++)

            {

                if (dgw.Columns.Contains(columnsToExport[i]))

                {

                    ExcelApp.Cells[1, columnExcel] = dgw.Columns[columnsToExport[i]].HeaderText;

                    columnExcel++;

                }

            }

            columnExcel = 1;

            foreach (string item in columns)

            {

                for (int i = 0; i < dgw.Rows.Count; i++)

                {

                    ExcelApp.Cells[i + 2, columnExcel] = dgw.Rows[i].Cells[item].Value.ToString();

                }

                columnExcel++;

            }

            ExcelApp.Visible = visible;

            if (!String.IsNullOrEmpty(path))

            {

                ExcelApp.ActiveWorkbook.SaveCopyAs(path);

                ExcelApp.ActiveWorkbook.Saved = true;

            }

            if (quit)

                ExcelApp.Quit();

        }