我在C#（ApplicationClass）中使用Excel互操作，并在finally子句中放置了以下代码：
while (System.Runtime.InteropServices.Marshal.ReleaseComObject(excelSheet) != 0) { }
excelSheet = null;
GC.Collect();
GC.WaitForPendingFinalizers();
尽管这种方法有效，但即使在我关闭Excel之后，Excel.exe进程仍处于后台。它只在我的应用程序被手动关闭后发布。
我做错了什么，或者是否有其他方法可以确保正确处理互操作对象？
当前回答
我有一个想法，尝试关闭你打开的excel进程：
在打开exclapplication之前，获取名为oldProcessIds的所有进程ID。打开重叠部分。现在获取名为nowProcessIds的所有超应用进程ID。当需要退出时，杀死oldProcessIds和nowProcessIds之间的except id。私有静态Excel.Application GetExcelApp（）{如果（_excelApp==空）{var processIds=System.Diagnostics.Process.GetProcessesByName（“EXCEL”）.Select（a=>a.Id）.ToList（）；_excelApp=新建Excel.Application（）；_excelApp.DisplayAlerts=false；_excelApp.Visible=false；_excelApp.ScreenUpdate=false；var newProcessIds=System.Diagnostics.Process.GetProcessesByName（“EXCEL”）.Select（a=>a.Id）.ToList（）；_excelApplicationProcessId=newProcessIds.Except（processIds）.FirstOrDefault（）；}return _excelApp；}公共静态void Dispose（）{尝试{_excelApp.Workbooks.Close（）；_excelApp.Quit（）；System.Runtime.InteropServices.Marsal.ReleaseComObject（_excelApp）；_excelApp=空；GC.Collect（）；GC.WaitForPendingFinalizers（）；if（_excelApplicationProcessId！=默认值（int））{var process=System.Diagnostics.process.GetProcessById（_excelApplicationProcessId）；过程Kill（）；_excelApplicationProcessId=默认值（int）；}}catch（异常ex）{_excelApp=空；}}
其他回答
我真的很喜欢当事情在自己身上清理干净。。。所以我做了一些包装类，为我做所有的清理工作！这些将进一步记录下来。
最终代码非常可读和可访问。在我关闭（）工作簿并退出（）应用程序之后，我还没有发现任何Excel的虚拟实例在运行（除了在调试和关闭应用程序的过程中）。
function void OpenCopyClose() {
var excel = new ExcelApplication();
var workbook1 = excel.OpenWorkbook("C:\Temp\file1.xslx", readOnly: true);
var readOnlysheet = workbook1.Worksheet("sheet1");
var workbook2 = excel.OpenWorkbook("C:\Temp\file2.xslx");
var writeSheet = workbook.Worksheet("sheet1");
// do all the excel manipulation
// read from the first workbook, write to the second workbook.
var a1 = workbook1.Cells[1, 1];
workbook2.Cells[1, 1] = a1
// explicit clean-up
workbook1.Close(false);
workbook2 .Close(true);
excel.Quit();
}
注意：您可以跳过Close（）和Quit（）调用，但如果您正在写入Excel文档，则至少需要Save（）。当对象超出范围（方法返回）时，类终结器将自动启动并进行任何清理。只要小心变量的作用域，工作表COM对象中对COM对象的任何引用都将被自动管理和清理，例如，只有在存储对COM对象引用时，才将变量保持在当前作用域的本地。如果需要，您可以轻松地将所需的值复制到POCO，或者创建其他包装类，如下所述。
为了管理所有这些，我创建了一个类DisposableComObject，它充当任何COM对象的包装器。它实现了IDisposable接口，还为不喜欢使用的用户提供了一个终结器。
Dispose（）方法调用Marshal.ReleaseComObject（ComObject），然后将ComObjectRef属性设置为null。
当私有ComObjectRef属性为null时，对象处于已释放状态。
如果在释放后访问ComObject属性，则会引发ComObjectAccessedAfterDisposeException异常。
可以手动调用Dispose（）方法。它也由终结器在using块结束时调用，并在该变量的作用域结束时使用var。
Microsoft.Office.Interop.Excel、Application、Workbook和Worksheet中的顶级类都有自己的包装类，每个包装类都是DisposableComObject的子类
代码如下：
/// <summary>
/// References to COM objects must be explicitly released when done.
/// Failure to do so can result in odd behavior and processes remaining running after the application has stopped.
/// This class helps to automate the process of disposing the references to COM objects.
/// </summary>
public abstract class DisposableComObject : IDisposable
{
public class ComObjectAccessedAfterDisposeException : Exception
{
public ComObjectAccessedAfterDisposeException() : base("COM object has been accessed after being disposed") { }
}
/// <summary>The actual COM object</summary>
private object ComObjectRef { get; set; }
/// <summary>The COM object to be used by subclasses</summary>
/// <exception cref="ComObjectAccessedAfterDisposeException">When the COM object has been disposed</exception>
protected object ComObject => ComObjectRef ?? throw new ComObjectAccessedAfterDisposeException();
public DisposableComObject(object comObject) => ComObjectRef = comObject;
/// <summary>
/// True, if the COM object has been disposed.
/// </summary>
protected bool IsDisposed() => ComObjectRef is null;
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this); // in case a subclass implements a finalizer
}
/// <summary>
/// This method releases the COM object and removes the reference.
/// This allows the garbage collector to clean up any remaining instance.
/// </summary>
/// <param name="disposing">Set to true</param>
protected virtual void Dispose(bool disposing)
{
if (!disposing || IsDisposed()) return;
Marshal.ReleaseComObject(ComObject);
ComObjectRef = null;
}
~DisposableComObject()
{
Dispose(true);
}
}
还有一个方便的泛型子类，使用起来稍微简单一些。
public abstract class DisposableComObject<T> : DisposableComObject
{
protected new T ComObject => (T)base.ComObject;
public DisposableComObject(T comObject) : base(comObject) { }
}
最后，我们可以使用DisposableComObject＜T＞为Excel互操作类创建包装类。
ExcelApplication子类引用了一个新的Excel应用程序实例，用于打开工作簿。
OpenWorkbook（）返回一个ExcelWorkbook，它也是DisposableComObject的子类。
在调用基Dispose（）方法之前，Dispose（（）已被重写以退出Excel应用程序。Quit（）是Dispose（）的别名。
public class ExcelApplication : DisposableComObject<Application>
{
public class OpenWorkbookActionCancelledException : Exception
{
public string Filename { get; }
public OpenWorkbookActionCancelledException(string filename, COMException ex) : base($"The workbook open action was cancelled. {ex.Message}", ex) => Filename = filename;
}
/// <summary>The actual Application from Interop.Excel</summary>
Application App => ComObject;
public ExcelApplication() : base(new Application()) { }
/// <summary>Open a workbook.</summary>
public ExcelWorkbook OpenWorkbook(string filename, bool readOnly = false, string password = null, string writeResPassword = null)
{
try
{
var workbook = App.Workbooks.Open(Filename: filename, UpdateLinks: (XlUpdateLinks)0, ReadOnly: readOnly, Password: password, WriteResPassword: writeResPassword, );
return new ExcelWorkbook(workbook);
}
catch (COMException ex)
{
// If the workbook is already open and the request mode is not read-only, the user will be presented
// with a prompt from the Excel application asking if the workbook should be opened in read-only mode.
// This exception is raised when when the user clicks the Cancel button in that prompt.
throw new OpenWorkbookActionCancelledException(filename, ex);
}
}
/// <summary>Quit the running application.</summary>
public void Quit() => Dispose(true);
/// <inheritdoc/>
protected override void Dispose(bool disposing)
{
if (!disposing || IsDisposed()) return;
App.Quit();
base.Dispose(disposing);
}
}
ExcelWorkbook还子类DisposableComObject＜Workbook＞，用于打开工作表。
Worksheet（）方法返回ExcelWorksheet，您猜到了，它也是DisposableComObject＜Workbook＞的子类。
Dispose（）方法被重写，首先关闭工作表，然后调用基Dispose（（）。
注意：我添加了一些扩展方法，用于迭代Workbook.Worksheets。如果您遇到编译错误，这就是原因。我将在末尾添加扩展方法。
public class ExcelWorkbook : DisposableComObject<Workbook>
{
public class WorksheetNotFoundException : Exception
{
public WorksheetNotFoundException(string message) : base(message) { }
}
/// <summary>The actual Workbook from Interop.Excel</summary>
Workbook Workbook => ComObject;
/// <summary>The worksheets within the workbook</summary>
public IEnumerable<ExcelWorksheet> Worksheets => worksheets ?? (worksheets = Workbook.Worksheets.AsEnumerable<Worksheet>().Select(w => new ExcelWorksheet(w)).ToList());
private IEnumerable<ExcelWorksheet> worksheets;
public ExcelWorkbook(Workbook workbook) : base(workbook) { }
/// <summary>
/// Get the worksheet matching the <paramref name="sheetName"/>
/// </summary>
/// <param name="sheetName">The name of the Worksheet</param>
public ExcelWorksheet Worksheet(string sheetName) => Worksheet(s => s.Name == sheetName, () => $"Worksheet not found: {sheetName}");
/// <summary>
/// Get the worksheet matching the <paramref name="predicate"/>
/// </summary>
/// <param name="predicate">A function to test each Worksheet for a macth</param>
public ExcelWorksheet Worksheet(Func<ExcelWorksheet, bool> predicate, Func<string> errorMessageAction) => Worksheets.FirstOrDefault(predicate) ?? throw new WorksheetNotFoundException(errorMessageAction.Invoke());
/// <summary>
/// Returns true of the workbook is read-only
/// </summary>
public bool IsReadOnly() => Workbook.ReadOnly;
/// <summary>
/// Save changes made to the workbook
/// </summary>
public void Save()
{
Workbook.Save();
}
/// <summary>
/// Close the workbook and optionally save changes
/// </summary>
/// <param name="saveChanges">True is save before close</param>
public void Close(bool saveChanges)
{
if (saveChanges) Save();
Dispose(true);
}
/// <inheritdoc/>
protected override void Dispose(bool disposing)
{
if (!disposing || IsDisposed()) return;
Workbook.Close();
base.Dispose(disposing);
}
}
最后是ExcelWorksheet。
UsedRows（）只返回未展开的Microsoft.Office.Interop.Excel.Range对象的可枚举值。我还没有遇到这样的情况，即从Microsoft.Office.Interop.Excel.Worksheet对象的财产访问的COM对象需要手动包装，就像应用程序、工作簿和工作表需要那样。这些似乎都能自动清理它们。大多数情况下，我只是在Ranges上迭代并获取或设置值，所以我的特定用例不如可用功能那么先进。
在这种情况下，不需要重写Dispose（），因为不需要对工作表执行任何特殊操作。
public class ExcelWorksheet : DisposableComObject<Worksheet>
{
/// <summary>The actual Worksheet from Interop.Excel</summary>
Worksheet Worksheet => ComObject;
/// <summary>The worksheet name</summary>
public string Name => Worksheet.Name;
// <summary>The worksheets cells (Unwrapped COM object)</summary>
public Range Cells => Worksheet.Cells;
public ExcelWorksheet(Worksheet worksheet) : base(worksheet) { }
/// <inheritdoc cref="WorksheetExtensions.UsedRows(Worksheet)"/>
public IEnumerable<Range> UsedRows() => Worksheet.UsedRows().ToList();
}
可以添加更多的包装类。只需根据需要向ExcelWorksheet添加其他方法，并在包装类中返回COM对象。只需复制我们通过ExcelApplication.OpenWorkbook（）和ExcelWorkbook.WorkSheets包装工作簿时所做的操作。
一些有用的扩展方法：
public static class EnumeratorExtensions
{
/// <summary>
/// Converts the <paramref name="enumerator"/> to an IEnumerable of type <typeparamref name="T"/>
/// </summary>
public static IEnumerable<T> AsEnumerable<T>(this IEnumerable enumerator)
{
return enumerator.GetEnumerator().AsEnumerable<T>();
}
/// <summary>
/// Converts the <paramref name="enumerator"/> to an IEnumerable of type <typeparamref name="T"/>
/// </summary>
public static IEnumerable<T> AsEnumerable<T>(this IEnumerator enumerator)
{
while (enumerator.MoveNext()) yield return (T)enumerator.Current;
}
/// <summary>
/// Converts the <paramref name="enumerator"/> to an IEnumerable of type <typeparamref name="T"/>
/// </summary>
public static IEnumerable<T> AsEnumerable<T>(this IEnumerator<T> enumerator)
{
while (enumerator.MoveNext()) yield return enumerator.Current;
}
}
public static class WorksheetExtensions
{
/// <summary>
/// Returns the rows within the used range of this <paramref name="worksheet"/>
/// </summary>
/// <param name="worksheet">The worksheet</param>
public static IEnumerable<Range> UsedRows(this Worksheet worksheet) =>
worksheet.UsedRange.Rows.AsEnumerable<Range>();
}
我找到了一个有用的通用模板，它可以帮助实现COM对象的正确处置模式，这些对象在超出范围时需要调用Marshal.ReleaseComObject：
用法：
using (AutoReleaseComObject<Application> excelApplicationWrapper = new AutoReleaseComObject<Application>(new Application()))
{
try
{
using (AutoReleaseComObject<Workbook> workbookWrapper = new AutoReleaseComObject<Workbook>(excelApplicationWrapper.ComObject.Workbooks.Open(namedRangeBase.FullName, false, false, missing, missing, missing, true, missing, missing, true, missing, missing, missing, missing, missing)))
{
// do something with your workbook....
}
}
finally
{
excelApplicationWrapper.ComObject.Quit();
}
}
模板：
public class AutoReleaseComObject<T> : IDisposable
{
private T m_comObject;
private bool m_armed = true;
private bool m_disposed = false;
public AutoReleaseComObject(T comObject)
{
Debug.Assert(comObject != null);
m_comObject = comObject;
}
#if DEBUG
~AutoReleaseComObject()
{
// We should have been disposed using Dispose().
Debug.WriteLine("Finalize being called, should have been disposed");
if (this.ComObject != null)
{
Debug.WriteLine(string.Format("ComObject was not null:{0}, name:{1}.", this.ComObject, this.ComObjectName));
}
//Debug.Assert(false);
}
#endif
public T ComObject
{
get
{
Debug.Assert(!m_disposed);
return m_comObject;
}
}
private string ComObjectName
{
get
{
if(this.ComObject is Microsoft.Office.Interop.Excel.Workbook)
{
return ((Microsoft.Office.Interop.Excel.Workbook)this.ComObject).Name;
}
return null;
}
}
public void Disarm()
{
Debug.Assert(!m_disposed);
m_armed = false;
}
#region IDisposable Members
public void Dispose()
{
Dispose(true);
#if DEBUG
GC.SuppressFinalize(this);
#endif
}
#endregion
protected virtual void Dispose(bool disposing)
{
if (!m_disposed)
{
if (m_armed)
{
int refcnt = 0;
do
{
refcnt = System.Runtime.InteropServices.Marshal.ReleaseComObject(m_comObject);
} while (refcnt > 0);
m_comObject = default(T);
}
m_disposed = true;
}
}
}
参考：
http://www.deez.info/sengelha/2005/02/11/useful-idisposable-class-3-autoreleasecomobject/
Excel命名空间中的任何内容都需要发布。时期
你不能这样做：
Worksheet ws = excel.WorkBooks[1].WorkSheets[1];
你必须这样做
Workbooks books = excel.WorkBooks;
Workbook book = books[1];
Sheets sheets = book.WorkSheets;
Worksheet ws = sheets[1];
随后释放物体。
这对我正在进行的一个项目起到了作用：
excelApp.Quit();
Marshal.ReleaseComObject (excelWB);
Marshal.ReleaseComObject (excelApp);
excelApp = null;
我们了解到，在使用Excel COM对象时，将其每个引用都设置为空非常重要。这包括单元格、工作表和所有内容。
我认为其中一些只是框架处理Office应用程序的方式，但我可能错了。在某些日子，一些应用程序会立即清理进程，而在其他日子，似乎要等到应用程序关闭。总的来说，我不再关注细节，只是确保一天结束时没有任何额外的流程。
还有，也许我过于简化了，但我想你可以。。。
objExcel = new Excel.Application();
objBook = (Excel.Workbook)(objExcel.Workbooks.Add(Type.Missing));
DoSomeStuff(objBook);
SaveTheBook(objBook);
objBook.Close(false, Type.Missing, Type.Missing);
objExcel.Quit();
正如我之前所说，我不太关注Excel进程出现或消失的细节，但这通常对我有用。我也不喜欢在最短的时间内保持Excel进程，但我可能只是在这方面有点偏执。
