✔ DataGridView in Excel exportieren

        private void toolStripButtonExcel_Click(object sender, EventArgs e)
        {
            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
            {
                Microsoft.Office.Interop.Excel.ApplicationClass ExcelApp = new Microsoft.Office.Interop.Excel.ApplicationClass();

                ExcelApp.Application.Workbooks.Add(Type.Missing);
                ExcelApp.Columns.ColumnWidth = 20;

                int k = 0;
                foreach (DataGridViewColumn column in aDataGridView.Columns)
                {
                    ExcelApp.Cells[1, k + 1] = column.HeaderText.ToString();
                    k++;
                }

                for (int i = 2; i < aDataGridView.Rows.Count; i++)
                {
                    DataGridViewRow row = aDataGridView.Rows[i];
                    for (int j = 0; j < row.Cells.Count; j++)
                    {
                        ExcelApp.Cells[i + 1, j + 1] = row.Cells[j].FormattedValue.ToString();
                    }
                }

                ExcelApp.ActiveWorkbook.SaveCopyAs(saveFileDialog1.FileName);
                ExcelApp.ActiveWorkbook.Saved = true;

                ExcelApp.Quit();
            }
        }