Question

我正在尝试使用Filehelpers ExcelNPOIStorage从Excel工作表中提取数据。因此我创建了一个类：

public static class UalExcelReader
    {
        public static UalShipmentRecord[] ReadInput(String pathToFile)
        {
            var provider = new ExcelNPOIStorage(typeof (UalShipmentRecord))
            {
                StartRow = 2,
                StartColumn = 1,
                FileName = pathToFile
            };
            var res = (UalShipmentRecord[]) provider.ExtractRecords();
            return res;
        }
    }

当然还有模型类：

[DelimitedRecord("|")]
public class UalShipmentRecord
{
    public string contentofcol1;
    public string contentofcol2;
    ...

}

但是我收到一个名为ExtractRecords（）的IndexOutOfRangeException：

System.IndexOutOfRangeException was unhandled
  HResult=-2146233080
  Message=Index was outside the bounds of the array.
  Source=FileHelpers
  StackTrace:
       at FileHelpers.RecordOperations.ValuesToRecord(Object[] values)
       at FileHelpers.DataLink.DataStorage.ValuesToRecord(Object[] values)
       at FileHelpers.ExcelNPOIStorage.ExcelNPOIStorage.ExtractRecords()
       at Test.Controller.UalExcelReader.ReadInput(String pathToFile) in c:\TEMP\test\Test\Test\Test\Controller\UalExcelReader.cs:line 17
       at Test.App.OnStartup(StartupEventArgs eventArgs) in c:\TEMP\test\Test\Test\Test\App.xaml.cs:line 23
       at System.Windows.Application.<.ctor>b__1(Object unused)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.DispatcherOperation.InvokeImpl()
       at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.Run()
       at System.Windows.Application.RunDispatcher(Object ignore)
       at System.Windows.Application.RunInternal(Window window)
       at System.Windows.Application.Run(Window window)
       at System.Windows.Application.Run()
       at Test.App.Main() in c:\TEMP\test\Test\Test\Test\obj\Debug\App.g.cs:line 0
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

我正确使用它吗？有一个我可以看的例子吗？

Answer 1

1）当您的Excel工作表中有空白单元格时，可能会发生此错误。这似乎是ExcelNPOIStorage检索给定行的值的方式中的潜在问题。

NPOI正在使用NPOI.CellWalk来遍历每一行中的单元格，这似乎会跳过空白单元格。因此，Values数组比空白单元格的数量短。

看起来需要采用不同的方法，如下所述：http://poi.apache.org/spreadsheet/quick-guide.html#Iterator

2）当不存在时可能导致空白单元格的内容具有不正确的StartRow和StartColumn值。

与StartRow和StartColumn的智能感知评论相反，对于ExcelNPOIStorage，他们是基于0的（而在ExcelStorage中他们是从1开始的）

来源：https://github.com/MarcosMeli/FileHelpers/blob/master/FileHelpers.ExcelNPOIStorage/Test/Program.cs

鉴于我遇到的问题，我会在上面的评论中使用旧的ExcelStorage类，它更可靠，但缺点是它依赖于Excel Interop。

Answer 2

默认情况下，在HSSFWorkbook和XSSFWorkbook类中，NPOI库中的MissingCellPolicy设置为MissingCellPolicy.RETURN_NULL_AND_BLANK。

在相关工作簿实例上将值更改为MissingCellPolicy.CREATE_NULL_AS_BLANK可解决此问题。

FileHelpers.ExcelNPOIStorage
  ExcelNPOIStorage.cs（OpenWorkbook方法）
  修复第101行

  private void OpenWorkbook(string filename)
    {
        FileInfo info = new FileInfo(filename);
        if (info.Exists == false)
            throw new FileNotFoundException(string.Concat("Excel File '", filename, "' not found."), filename);

        using (FileStream file = new FileStream(filename, FileMode.Open, FileAccess.Read)) {
            var extension = Path.GetExtension(filename);
            if (extension.ToLowerInvariant() == ".xlsx" || extension.ToLowerInvariant() == ".xlsm")
            {
                mWorkbook = new XSSFWorkbook(file);
            }
            else
                mWorkbook = new HSSFWorkbook(file);
            // Next line fix
            Line 101 - mWorkbook.MissingCellPolicy = MissingCellPolicy.CREATE_NULL_AS_BLANK;
            // Previous line fix  
            if (String.IsNullOrEmpty(SheetName))
                mSheet = mWorkbook.GetSheetAt(mWorkbook.ActiveSheetIndex);  
            else {
                try {
                    mSheet = mWorkbook.GetSheet(SheetName);
                    if (mSheet == null) {
                        throw new ExcelBadUsageException(string.Concat("The sheet '",
                            SheetName,
                            "' was not found in the workbook."));
                    }

                    var sheetIndex = mWorkbook.GetSheetIndex(mSheet);
                    mWorkbook.SetActiveSheet(sheetIndex);
                }
                catch {
                    throw new ExcelBadUsageException(string.Concat("The sheet '",
                        SheetName,
                        "' was not found in the workbook."));
                }
            }
        }
    }

在github repo上修复的url下面

https://github.com/MarcosMeli/FileHelpers/pull/291

Answer 3

我认为空单元格是一个问题。在我的文件中，我只是在文件中绕数据边缘，这对我有所帮助。尝试用鼠标标记数据并打开字段周围的边缘。

如何使用C＃/ FileHelpers ExcelNPOIStorage

3 个答案: