How I can add my datagridview in an existing excel file using c#

Question

Hello well I have this problem,The code only it can create a new excle file but I want to export my datagrid in a existing excel file. Any help is appreciated.

     try
        {
            if (DataGridView1.DataSource != null)
            {
                SaveFileDialog fichero = new SaveFileDialog();
                fichero.Filter = "Excel (*.xls)|*.xls";
                if (fichero.ShowDialog() == DialogResult.OK)
                {
                    Microsoft.Office.Interop.Excel.Application aplicacion;
                    Microsoft.Office.Interop.Excel.Workbook libros_trabajo;
                    Microsoft.Office.Interop.Excel.Worksheet hoja_trabajo;
                    aplicacion = new Microsoft.Office.Interop.Excel.Application();
                    libros_trabajo = aplicacion.Workbooks.Add();
                    hoja_trabajo = (Microsoft.Office.Interop.Excel.Worksheet)libros_trabajo.Worksheets.get_Item(1);

                    //exportar cabeceras DataGridView1
                    for (int i = 1; i <= this.DataGridView1.Columns.Count; i++)
                    {
                        hoja_trabajo.Cells[1, i] = this.DataGridView1.Columns[i - 1].HeaderText;
                    }

                    //Recorremos el DataGridView rellenando la hoja de trabajo con los datos
                    for (int i = 0; i < this.DataGridView1.Rows.Count - 1; i++)
                    {
                        for (int j = 0; j < this.DataGridView1.Columns.Count; j++)
                        {
                            hoja_trabajo.Cells[i + 2, j + 1] = this.DataGridView1.Rows[i].Cells[j].Value.ToString();
                        }
                    }

                    libros_trabajo.SaveAs(fichero.FileName, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal);
                    libros_trabajo.Close(true);
                    aplicacion.Quit();
                }
            }
        }

Answer 1

Pertinent to your task, use the underlying DataTable

DataTable dt = DataGridView1.DataSource as DataTable;

and export data from that DataTable dt to Excel using the following procedure, which utilizes Microsoft.Office.Interop.Excel object library:

/// <summary>
/// export DataTable to Excel (C#)
/// </summary>
internal static void Export2Excel(DataTable dataTable)
{
    object misValue = System.Reflection.Missing.Value;
    Microsoft.Office.Interop.Excel.Application _appExcel = null;
    Microsoft.Office.Interop.Excel.Workbook _excelWorkbook = null;
    Microsoft.Office.Interop.Excel.Worksheet _excelWorksheet = null;
    try
    {
        // excel app object
        _appExcel = new Microsoft.Office.Interop.Excel.Application();

        // excel workbook object added to app
        _excelWorkbook = _appExcel.Workbooks.Add(misValue);

        _excelWorksheet = _appExcel.ActiveWorkbook.ActiveSheet as Microsoft.Office.Interop.Excel.Worksheet;

        // column names row (range obj)
        Microsoft.Office.Interop.Excel.Range _columnsNameRange;
        _columnsNameRange = _excelWorksheet.get_Range("A1", misValue).get_Resize(1, dataTable.Columns.Count);

        // column names array to be assigned to _columnNameRange
        string[] _arrColumnNames = new string[dataTable.Columns.Count];

        for (int i = 0; i < dataTable.Columns.Count; i++)
        {
            // array of column names
            _arrColumnNames[i] = dataTable.Columns[i].ColumnName;
        }

        // assign array to column headers range, make 'em bold
        _columnsNameRange.set_Value(misValue, _arrColumnNames);
        _columnsNameRange.Font.Bold = true;

        // populate data content row by row
        for (int Idx = 0; Idx < dataTable.Rows.Count; Idx++)
        {
            _excelWorksheet.Range["A2"].Offset[Idx].Resize[1, dataTable.Columns.Count].Value =
            dataTable.Rows[Idx].ItemArray;
        }

        // Autofit all Columns in the range
        _columnsNameRange.Columns.EntireColumn.AutoFit();
    }
    catch { throw; }
}

just pass dt as an argument. Optionally, upon data export completion you can save the Workbook and Quit Excel app. Furthermore, as mentioned in the comments thread, you can open the existing Excel file (eg "MyExcelFile") and export data to that file, or just re-write the existing file by saving the newly created Workbook (ie _excelWorkbook ) under the old file name.

The core idea of proposed solution is to run data export procedure on the underlying DataTable rather than DataGridView and export entire data Row at once (instead of cell-by-cell) for better performance.

Hope this may help.