将DataTable数据保存在Excel文件asp.Net中

Question

I have a Gridview which i fill with a Datatable. On the webpage the user has to be able to download an excel file with the contents of the Gridview. So mi thought the easiest way to save the files is to save the datatable as an excel file. I have troied this method, which i found here on stackoverflow.

using Excel = Microsoft.Office.Interop.Excel;
 public static bool ExportDataTableToExcel(DataTable dt, string filepath)
    {

    Excel.Application oXL;
    Excel.Workbook oWB;
    Excel.Worksheet oSheet;
    Excel.Range oRange;

    try
    {
        // Start Excel and get Application object. 
        oXL = new Excel.Application();

        // Set some properties 
        oXL.Visible = true;
        oXL.DisplayAlerts = false;

        // Get a new workbook. 
        oWB = oXL.Workbooks.Add(Missing.Value);

        // Get the Active sheet 
        oSheet = (Excel.Worksheet)oWB.ActiveSheet;
        oSheet.Name = "Data";

        int rowCount = 1;
        foreach (DataRow dr in dt.Rows)
        {
            rowCount += 1;
            for (int i = 1; i < dt.Columns.Count + 1; i++)
            {
                // Add the header the first time through 
                if (rowCount == 2)
                {
                    oSheet.Cells[1, i] = dt.Columns[i - 1].ColumnName;
                }
                oSheet.Cells[rowCount, i] = dr[i - 1].ToString();
            }
        }

        // Resize the columns 
        oRange = oSheet.get_Range(oSheet.Cells[1, 1],
                      oSheet.Cells[rowCount, dt.Columns.Count]);
        oRange.EntireColumn.AutoFit();

        // Save the sheet and close 
        oSheet = null;
        oRange = null;
        oWB.SaveAs(filepath, Excel.XlFileFormat.xlWorkbookNormal,
            Missing.Value, Missing.Value, Missing.Value, Missing.Value,
            Excel.XlSaveAsAccessMode.xlExclusive,
            Missing.Value, Missing.Value, Missing.Value,
            Missing.Value, Missing.Value);
        oWB.Close(Missing.Value, Missing.Value, Missing.Value);
        oWB = null;
        oXL.Quit();
    }
    catch
    {
        throw;
    }
    finally
    {
        // Clean up 
        // NOTE: When in release mode, this does the trick 
        GC.WaitForPendingFinalizers();
        GC.Collect();
        GC.WaitForPendingFinalizers();
        GC.Collect();
    }

    return true;
}

Bu i get a build error stating that "The name Missing does not exist in the current context" and i cant seem to figure out why? can anyone help ?

the code is pasted from this stackoverflow page here

Answer 1

According to msdn here , Missing.Value is defined in System.Reflection . You should add a reference to this namespace.

using System.Reflection;