首先：C# 中的后期绑定非常痛苦。最好避免它。
第二：C# 中的后期绑定很痛苦。使用 PIA！
好的，话虽如此，要使用后期绑定，您需要执行以下操作：删除对 Office 2003 PIA 的引用，而是添加AccessibleObjectFromWindow 所需接口的 COM 导入，即@987654325 @接口：
[Guid("00020893-0000-0000-C000-000000000046")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface ExcelWindow
{
}
您可以使用Reflector 之类的工具检索此接口（或者在您的项目中仍然引用 Excel PIA 时，只需在类型 Excel.Window 上按 F12）
完成后，您必须修改AccessibleObjectFromWindow 的签名以匹配导入的ExcelWindow 接口：
[DllImport("Oleacc.dll")]
static extern int AccessibleObjectFromWindow(int hwnd, uint dwObjectID, byte[] riid, out ExcelWindow ptr);
最后，必须使用反射从ExcelWindow对象中获取Excel.Application对象：
object xlApp = ptr.GetType().InvokeMember("Application", BindingFlags.GetProperty, null, ptr, null);
如果您的代码要对 Excel 的 OM 进行大量调用，则在关闭 Option Strict 的情况下使用 VB 可能会更容易（或等待 C#4.0 ;-)。或者，如果您不想从 C# 进行更改，最好为后期绑定调用创建一个包装类。
完整样本
这是一个功能齐全的示例（基于 Andrew Whitechapel 的 article）：
using System;
using System.Globalization;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
namespace ExcelLateBindingSample
{
/// <summary>
/// Interface definition for Excel.Window interface
/// </summary>
[Guid("00020893-0000-0000-C000-000000000046")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface ExcelWindow
{
}
/// <summary>
/// This class is needed as a workaround to http://support.microsoft.com/default.aspx?scid=kb;en-us;320369
/// Excel automation will fail with the follwoing error on systems with non-English regional settings:
/// "Old format or invalid type library. (Exception from HRESULT: 0x80028018 (TYPE_E_INVDATAREAD))"
/// </summary>
class UILanguageHelper : IDisposable
{
private CultureInfo _currentCulture;
public UILanguageHelper()
{
// save current culture and set culture to en-US
_currentCulture = System.Threading.Thread.CurrentThread.CurrentCulture;
System.Threading.Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
}
public void Dispose()
{
// reset to original culture
System.Threading.Thread.CurrentThread.CurrentCulture = _currentCulture;
}
}
class Program
{
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("Oleacc.dll")]
static extern int AccessibleObjectFromWindow(int hwnd, uint dwObjectID, byte[] riid, out ExcelWindow ptr);
public delegate bool EnumChildCallback(int hwnd, ref int lParam);
[DllImport("User32.dll")]
public static extern bool EnumChildWindows(int hWndParent, EnumChildCallback lpEnumFunc, ref int lParam);
[DllImport("User32.dll")]
public static extern int GetClassName(int hWnd, StringBuilder lpClassName, int nMaxCount);
public static bool EnumChildProc(int hwndChild, ref int lParam)
{
StringBuilder buf = new StringBuilder(128);
GetClassName(hwndChild, buf, 128);
if (buf.ToString() == "EXCEL7")
{
lParam = hwndChild;
return false;
}
return true;
}
static void Main(string[] args)
{
// Use the window class name ("XLMAIN") to retrieve a handle to Excel's main window.
// Alternatively you can get the window handle via the process id:
// int hwnd = (int)Process.GetProcessById(excelPid).MainWindowHandle;
//
int hwnd = (int)FindWindow("XLMAIN", null);
if (hwnd != 0)
{
int hwndChild = 0;
// Search the accessible child window (it has class name "EXCEL7")
EnumChildCallback cb = new EnumChildCallback(EnumChildProc);
EnumChildWindows(hwnd, cb, ref hwndChild);
if (hwndChild != 0)
{
// We call AccessibleObjectFromWindow, passing the constant OBJID_NATIVEOM (defined in winuser.h)
// and IID_IDispatch - we want an IDispatch pointer into the native object model.
//
const uint OBJID_NATIVEOM = 0xFFFFFFF0;
Guid IID_IDispatch = new Guid("{00020400-0000-0000-C000-000000000046}");
ExcelWindow ptr;
int hr = AccessibleObjectFromWindow(hwndChild, OBJID_NATIVEOM, IID_IDispatch.ToByteArray(), out ptr);
if (hr >= 0)
{
// We successfully got a native OM IDispatch pointer, we can QI this for
// an Excel Application using reflection (and using UILanguageHelper to
// fix http://support.microsoft.com/default.aspx?scid=kb;en-us;320369)
//
using (UILanguageHelper fix = new UILanguageHelper())
{
object xlApp = ptr.GetType().InvokeMember("Application", BindingFlags.GetProperty, null, ptr, null);
object version = xlApp.GetType().InvokeMember("Version", BindingFlags.GetField | BindingFlags.InvokeMethod | BindingFlags.GetProperty, null, xlApp, null);
Console.WriteLine(string.Format("Excel version is: {0}", version));
}
}
}
}
}
}
}
这将是在 VB 中没有 PIA 的相同解决方案（请注意，OM 调用更具可读性；但是，访问 OM 的代码将是相同的）：
Option Strict Off
Imports System.Globalization
Imports System.Runtime.InteropServices
Imports System.Text
Module ExcelLateBindingSample
''' <summary>
''' Interface definition for Excel.Window interface
''' </summary>
<Guid("00020893-0000-0000-C000-000000000046"), _
InterfaceType(ComInterfaceType.InterfaceIsIDispatch)> _
Public Interface ExcelWindow
End Interface
''' <summary>
''' This class is needed as a workaround to http://support.microsoft.com/default.aspx?scid=kb;en-us;320369
''' Excel automation will fail with the follwoing error on systems with non-English regional settings:
''' "Old format or invalid type library. (Exception from HRESULT: 0x80028018 (TYPE_E_INVDATAREAD))"
''' </summary>
Class UILanguageHelper
Implements IDisposable
Private _currentCulture As CultureInfo
Public Sub New()
' save current culture and set culture to en-US
_currentCulture = System.Threading.Thread.CurrentThread.CurrentCulture
System.Threading.Thread.CurrentThread.CurrentCulture = New CultureInfo("en-US")
End Sub
Public Sub Dispose() Implements System.IDisposable.Dispose
'reset to original culture
System.Threading.Thread.CurrentThread.CurrentCulture = _currentCulture
End Sub
End Class
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Function FindWindow(ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
End Function
<DllImport("Oleacc.dll")> _
Private Function AccessibleObjectFromWindow(ByVal hwnd As Integer, ByVal dwObjectID As UInt32, ByVal riid() As Byte, ByRef ptr As ExcelWindow) As Integer
End Function
Public Delegate Function EnumChildCallback(ByVal hwnd As Integer, ByRef lParam As Integer) As Boolean
<DllImport("User32.dll")> _
Public Function EnumChildWindows(ByVal hWndParent As Integer, ByVal lpEnumFunc As EnumChildCallback, ByRef lParam As Integer) As Boolean
End Function
<DllImport("User32.dll")> _
Public Function GetClassName(ByVal hWnd As Integer, ByVal lpClassName As StringBuilder, ByVal nMaxCount As Integer) As Integer
End Function
Public Function EnumChildProc(ByVal hwndChild As Integer, ByRef lParam As Integer) As Boolean
Dim buf As New StringBuilder(128)
GetClassName(hwndChild, buf, 128)
If buf.ToString() = "EXCEL7" Then
lParam = hwndChild
Return False
End If
Return True
End Function
Sub Main()
' Use the window class name ("XLMAIN") to retrieve a handle to Excel's main window.
' Alternatively you can get the window handle via the process id:
' Dim hwnd As Integer = CInt(Process.GetProcessById(excelPid).MainWindowHandle);
'
Dim hwnd As Integer = CInt(FindWindow("XLMAIN", Nothing))
If hwnd <> 0 Then
Dim hwndChild As Integer = 0
' Search the accessible child window (it has class name "EXCEL7")
Dim cb As New EnumChildCallback(AddressOf EnumChildProc)
EnumChildWindows(hwnd, cb, hwndChild)
If hwndChild <> 0 Then
' We call AccessibleObjectFromWindow, passing the constant OBJID_NATIVEOM (defined in winuser.h)
' and IID_IDispatch - we want an IDispatch pointer into the native object model.
'
Const OBJID_NATIVEOM As UInteger = &HFFFFFFF0&
Dim IID_IDispatch As New Guid("{00020400-0000-0000-C000-000000000046}")
Dim ptr As ExcelWindow
Dim hr As Integer = AccessibleObjectFromWindow(hwndChild, OBJID_NATIVEOM, IID_IDispatch.ToByteArray(), ptr)
If hr >= 0 Then
' We successfully got a native OM IDispatch pointer, we can QI this for
' an Excel Application using reflection (and using UILanguageHelper to
' fix http://support.microsoft.com/default.aspx?scid=kb;en-us;320369)
'
Using fixCrash As New UILanguageHelper
Console.WriteLine(String.Format("Excel version is: {0}", ptr.Application.Version))
End Using
End If
End If
End If
End Sub
End Module