在Excel应用程序COM对象上使用反射时没有事件

Question

我有一个Excel模板，用于通过以下方法链接到我的应用程序：

Excel VBA：

objApp.SetExcelApp Application

在我的应用程序代码中，我想使用反射来连接Excel应用程序上的WorkbookBeforeClose事件，这样当该事件触发时我就可以做一些事情：

VB.NET：

Public Sub SetExcelApp(ByRef objExcel As Object)
    Dim evWorkbookBeforeClose As Reflection.EventInfo = objExcel.GetType().GetEvent("WorkbookBeforeClose")
    Dim mEvents As Reflection.EventInfo() = objExcel.GetType().GetEvents()
    ' do stuff
End Sub

令人惊讶的是，evWorkbookBeforeClose是Nothing——甚至mEvents也是Nothing！

我可以很好地使用方法和属性。像objExcel.ActiveWorkbook和objExcel.Run("MyVBAMethod")

有人知道为什么这不起作用吗？这不可能使用反射吗？是否必须添加对Excel互操作的引用？

EDIT:因此，如果我添加Excel互操作作为引用，它将正常工作，因为我可以在事件上使用AddHandler。但我仍然想知道为什么使用反射不起作用。。。

我看到的一件有趣的事情是，即使我将其更改为objExcel As Microsoft.Office.Interop.Excel.Application，执行上述调用（GetEvent/GetEvents）仍然都返回Nothing！

Answer 1

可以使用System.Runtime.InteropServices.ComEventsHelper类添加事件。

例如

// source: http://www.guysmithferrier.com/downloads/csharp4.pdf
public static void ExcelExample() {
    Type ty = Type.GetTypeFromProgID("Excel.Application");
    Object o1 = Activator.CreateInstance(ty); // COM Object
    o1.GetType().InvokeMember("Visible", BindingFlags.SetProperty, null, o1, new Object[] { true });
    // Sh = Sheet?
    // Target = Range
    // 0x616 is the SelectionChanged event
    ComEventsHelper.Combine(o1, new Guid("00024413-0000-0000-C000-000000000046"), 0x616, new Action<Object,Object>((Sh, Target) => {
        int breakPoint = 1;
    }));
}
public static void WordExample() {
    Type ty = Type.GetTypeFromProgID("Word.Application");
    Object o1 = Activator.CreateInstance(ty); // COM Object
    o1.GetType().InvokeMember("Visible", BindingFlags.SetProperty, null, o1, new Object[] { true });
    //var wdg4 = new Guid("00020A01-0000-0000-C000-000000000046"); // ApplicationEvents4 (Word)
    //var wdg3 = new Guid("00020A00-0000-0000-C000-000000000046"); // ApplicationEvents3 (Word)
    //var wdg2 = new Guid("000209FE-0000-0000-C000-000000000046"); // ApplicationEvents2 (Word)
    var wdg1 = new Guid("000209F7-0000-0000-C000-000000000046"); // ApplicationEventsInterface (Word)
    // 2 = Quit event
    ComEventsHelper.Combine(o1, wdg1, 2, new Action(() => {
        int breakPoint = 1;
    }));
    // 4 = Document open
    ComEventsHelper.Combine(o1, wdg1, 4, new Action<Object>((Doc) => {
        int breakPoint = 1;
    }));
}

调度ID（dispid）值似乎没有MSDN引用。我在网上找到了一些来源，所以我会把它们发布在这里：

来源：https://social.msdn.microsoft.com/Forums/sqlserver/en-US/3625e60d-0e9c-4871-a0e8-bcedbbb31ce0/is-there-an-fixed-version-of-microsoftofficeinteropworddll-on-msdn?forum=worddev

单词：

[DispId(0x00000001)]
void Startup();
[DispId(0x00000002)]
void Quit();
[DispId(0x00000003)]
void DocumentChange();
[DispId(0x00000004)]
void DocumentOpen(Word.Document Doc);
[DispId(0x00000006)]
void DocumentBeforeClose(Word.Document Doc, ref bool Cancel);
[DispId(0x00000007)]
void DocumentBeforePrint(Word.Document Doc, ref bool Cancel);
[DispId(0x00000008)]
void DocumentBeforeSave(Word.Document Doc, ref bool SaveAsUI, ref bool Cancel);
[DispId(0x00000009)]
void NewDocument(Word.Document Doc);
[DispId(0x0000000a)]
void WindowActivate(Word.Document Doc, Word.Window Wn);
[DispId(0x0000000b)]
void WindowDeactivate(Word.Document Doc, Word.Window Wn);
[DispId(0x0000000c)]
void WindowSelectionChange(Word.Selection Sel);
[DispId(0x0000000d)]
void WindowBeforeRightClick(Word.Selection Sel, ref bool Cancel);
[DispId(0x0000000e)]
void WindowBeforeDoubleClick(Word.Selection Sel, ref bool Cancel);
[DispId(0x0000000f)]
void EPostagePropertyDialog(Word.Document Doc);
[DispId(0x00000010)]
void EPostageInsert(Word.Document Doc);
[DispId(0x00000011)]
void MailMergeAfterMerge(Word.Document Doc, Word.Document DocResult);
[DispId(0x00000012)]
void MailMergeAfterRecordMerge(Word.Document Doc);
[DispId(0x00000013)]
void MailMergeBeforeMerge(Word.Document Doc, int StartRecord, int endRecord, ref bool Cancel);
[DispId(0x00000014)]
void MailMergeBeforeRecordMerge(Word.Document Doc, ref bool Cancel);
[DispId(0x00000015)]
void MailMergeDataSourceLoad(Word.Document Doc);
[DispId(0x00000016)]
void MailMergeDataSourceValidate(Word.Document Doc, ref bool Handled);
[DispId(0x00000017)]
void MailMergeWizardSendToCustom(Word.Document Doc);
[DispId(0x00000018)]
void MailMergeWizardStateChange(Word.Document Doc, ref int FromState, ref int ToState, ref bool Handled);
[DispId(0x00000019)]
void WindowSize(Word.Document Doc, Word.Window Wn);

Excel:

来源：http://www.codeforge.com/read/240027/AppEvents.java__html

  @DISPID(1565)
  public void newWorkbook(Wb)
  @DISPID(1558)
  public void sheetSelectionChange(Sh, Target)
  @DISPID(1559)
  public void sheetBeforeDoubleClick(Sh, Target, Cancel);
  @DISPID(1560)
  public void sheetBeforeRightClick(Sh, Target, Cancel);
  @DISPID(1561)
  public void sheetActivate(Sh)
  @DISPID(1562)
  public void sheetDeactivate(Sh)
  @DISPID(1563)
  public void sheetCalculate(Sh)
  @DISPID(1564)
  public void sheetChange(Sh, Target)
  @DISPID(1567)
  public void workbookOpen(Wb)
  @DISPID(1568)
  public void workbookActivate(Wb)
  @DISPID(1569)
  public void workbookDeactivate(Wb)
  @DISPID(1570)
  public void workbookBeforeClose(Wb, Cancel)
  @DISPID(1571)
  public void workbookBeforeSave(Wb, SaveAsUI, Cancel)
  @DISPID(1572)
  public void workbookBeforePrint(Wb, Cancel)
  @DISPID(1573)
  public void workbookNewSheet(Wb, Sh)
  @DISPID(1574)
  public void workbookAddinInstall(Wb)
  @DISPID(1575)
  public void workbookAddinUninstall(Wb)
  @DISPID(1554)
  public void windowResize(Wb, Window)
  @DISPID(1556)
  public void windowActivate(Wb, Window)
  @DISPID(1557)
  public void windowDeactivate(Wb, Window)
  @DISPID(1854)
  public void sheetFollowHyperlink(Sh, Hyperlink)
  @DISPID(2157)
  public void sheetPivotTableUpdate(Sh, PivotTable)
  @DISPID(2160)
  public void workbookPivotTableCloseConnection(Wb, PivotTable)
  @DISPID(2161)
  public void workbookPivotTableOpenConnection(Wb, PivotTable)
  @DISPID(2289)
  public void workbookSync(Wb, SyncEventType)
  @DISPID(2290)
  public void workbookBeforeXmlImport(Wb, XmlMap, Url, IsRefresh, Cancel)
  @DISPID(2291)
  public void workbookAfterXmlImport(Wb, XmlMap, IsRefresh, Result)
  @DISPID(2292)
  public void workbookBeforeXmlExport(Wb, XmlMap, Url, Cancel)
  @DISPID(2293)
  public void workbookAfterXmlExport(Wb, XmlMap, Url, Result)
  @DISPID(2611)
  public void workbookRowsetComplete(Wb, Description, Sheet, Success)
  @DISPID(2612)
  public void afterCalculate()