为什么会出现这种使用（）给我一个错误？ [英] Why does this Using() give me an error?

问题描述

我想（实际上是上百个）打开一个Excel文件（S）。我打开应用程序，但要使用围绕每个我打开工作簿的使用（）功能。这是为什么造成错误？

I am trying to open an (hundreds actually) excel file(s). I open the application but want to use the Using() functionality around each of the workbooks I open. Why is this resulting in an error?

using (Excel.Workbook wbXL = appXL.Workbooks.Open(_sourceFullPath, Type.Missing, Excel.XlFileAccess.xlReadOnly))
{
    //stuff with wbXL
}

使用得到红色下划线并说：'Microsoft.Office.Interop.excel.Workbook：在使用语句中使用的类型必须是隐式转换为System.IDisposable的

using gets the red underline and says "'Microsoft.Office.Interop.excel.Workbook':Type used in a using statement must be implicitly convertible to 'System.IDisposable'.

如何使这项工作。

推荐答案

差不多它说什么？ - 你只能使用使用与实现IDisposable，类，以便在编译器知道井盖其中的函数，在定稿调用 - yourclass.Dispose（） Excel的互操作类没有实现这个

Pretty much what it says - you can only use using with classes that implement IDisposable, so that under the covers the compiler knows which function to call on finalisation - yourclass.Dispose(). The Excel interop classes don't implement this.

所以，你有两个选择：

1. 写出Excel.Workbook实现IDispose，要么公开对象本身来调用方法，或者包装这些方法太，如：

1. Write your own wrapper class for Excel.Workbook that implements IDispose and either exposes the object itself to call methods on, or wraps those methods too, e.g.

public class DisposableWorkbook : IDisposable
{
    private Excel.Workbook _workbook = null;

    public DisposableWorkbook(Excel.Application appXL, String path,
                              NotSureOfType otherArgument,
                              Excel.XlFileAccess access)
    {
        _workbook = appXL.Workbooks.Open(path, otherArgument, access);
    }

    public Excel.Workbook Workbook
    {
        get { return _workbook; }
    }

    public void Dispose()
    {
        if (workbook != null)
        {
            workbook.Close(Excel.XlSaveAction.xlDoNotSaveChanges,
                           workbookToClose);
            workbook = null;
        }
    }
}

using (DisposableWorkbook dwbXL = new DisposableWorkbook(appXL,
          _sourceFullPath, Type.Missing, Excel.XlFileAccess.xlReadOnly))
{
     Excel.Workbook wbXL = dwbXL.Workbook;
     // stuff with wbXL
}

实施<$ C的东西$ C>使用自己，如：

Excel.Workbook wbXL = null;
try
{
    wbxl = appXL.Workbooks.Open(_sourceFullPath, Type.Missing,
                                Excel.XlFileAccess.xlReadOnly);
    //stuff with wbXL
}
finally
{
    if (wbxl != null) wbxl.Close();
}

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