为什么本应保存的文件并没有真正保存？

Question

以下代码取自 this tutorial，用于使用 C# 创建和保存 Excel 文件：

using Excel = Microsoft.Office.Interop.Excel;

namespace WindowsFormsAppExcelTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void buttonCreateExcelFile_Click(object sender, EventArgs e)
        {
            Excel.Application xlApp;
            Excel.Workbook xlWorkBook;
            Excel.Worksheet xlWorkSheet;
            object misValue = System.Reflection.Missing.Value;
            xlApp = new Excel.Application();
            xlWorkBook = xlApp.Workbooks.Add(misValue);
            xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
            xlWorkSheet.Cells[1, 1] = "http://csharp.net-informations.com";
            xlWorkBook.SaveAs("csharp-Excel.xls",
                Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue,
                Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
            xlWorkBook.Close(true, misValue, misValue);
            xlApp.Quit(); 
            releaseObject(xlWorkSheet);
            releaseObject(xlWorkBook);
            releaseObject(xlApp);
            MessageBox.Show("Excel file created , you can find the file c:\csharp-Excel.xls"); 
        }

        private void releaseObject(object obj)
        {
            try
            {
                System.Runtime.InteropServices.Marshal.ReleaseComObject(obj); obj = null;
            }
            catch (Exception ex)
            {
                obj = null;
                MessageBox.Show("Exception Occured while releasing object " + ex.ToString());
            }
            finally
            {
                GC.Collect();
            }
        } 
    } // class
} // namespace

它似乎运行很好 -- 我看到了 MessageBox 信息，我可以逐步完成它，没有任何问题的迹象。但是该文件并没有像它应该的那样保存到硬盘驱动器。为什么不呢？

Answer 1

保存到特定的非根位置（子文件夹）有效，例如这个：

String savefullpath = @"C:\misc\csharpExcelTest.xls";
    xlWorkBook.SaveAs(savefullpath,
        Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue,
        Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);

文件确实保存到那个地方。

显然唯一的问题是试图保存到 C/root。甚至尝试显式保存到 root，如下所示：

String savefullpath = @"C:\csharpExcelTest.xls";

...（而不是简单地提供一个裸文件名）可耻地失败了，告诉我：

System.Runtime.InteropServices.COMException was unhandled
  HelpLink=C:\Program Files (x86)\Microsoft Office\Office1233\XLMAIN11.CHM
  HResult=-2146827284
  Message=Microsoft Office Excel cannot access the file 'C:'. There are several possible reasons:

• The file name or path does not exist.
• The file is being used by another program.
• The workbook you are trying to save has the same name as a currently open workbook.
    . . .

所以：保存到root以外的地方可以避免这个问题。

更新

此外，当我没有提供 folder/full 路径时，它似乎被保存到我的 "Documents library"，并假设它会保存到 C:。我今天早上刚好查看那个文件夹，在那里看到了文件。

为什么本应保存的文件并没有真正保存？

Why does the supposedly-saved file not really get saved?

c#

excel

office-interop

excel-interop

ole-automation

更新