如何使用后期绑定获取excel实例？

Question

我在用着

[DllImport("Oleacc.dll")]
static extern int AccessibleObjectFromWindow(
int hwnd, 
uint dwObjectID, 
byte[] riid,
ref Excel.Window ptr);

使用他的句柄获取 Excel 实例，我从 excel 实例的进程 ID 中获取。

这是我使用这些功能时的样子

const uint OBJID_NATIVEOM = 0xFFFFFFF0;
Guid IID_IDispatch = new Guid("{00020400-0000-0000-C000-000000000046}");
Excel.Window ptr = null;  
int hr = AccessibleObjectFromWindow(hwndChild, OBJID_NATIVEOM, 
          IID_IDispatch.ToByteArray(), ref ptr);

Object objApp = ptr.Application;

这种和平的代码效果很好，但唯一的问题是我必须添加对 Office 2003 主互操作程序集的引用。

如您所见，函数中的最后一个参数是我需要添加对 Pias 的引用的原因，所以我的问题是是否有办法避免使用互操作程序集，我尝试过后期绑定，但也许我一直做错了，因为我无法让它发挥作用。

Answer 1

第一：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，为了使用后期绑定，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Excel.Window接口：

[Guid("00020893-0000-0000-C000-000000000046")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface ExcelWindow
{
}

您可以使用Reflector之类的工具检索此界面（或者只需在Excel.Window类型上按 F12，同时对 Excel PIA 的引用仍在您的项目中）

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 的文章）：

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

Answer 2

请改用 AccessibleObjectFromWindow 的这个定义：

    [DllImport("Oleacc.dll")]
    private static extern int AccessibleObjectFromWindow(
        int hwnd, uint dwObjectID,
        byte[] riid,
        [MarshalAs(UnmanagedType.IUnknown)]ref object ptr);

Answer 3

第一个答案中的代码就像一个魅力。 Word 也是如此，底部还有一些 .NET 4.0 动态操作。

// http://stackoverflow.com/questions/779363/how-to-use-use-late-binding-to-get-excel-instance
// ReSharper disable InconsistentNaming

using System;
using System.Runtime.InteropServices;
using System.Globalization;
using System.Reflection;
using System.Text;

namespace LateBindingWord {
    /// <summary> Interface definition for Word.Window interface </summary>
    [Guid("00020962-0000-0000-C000-000000000046")]
    [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
    public interface IWordWindow {
    }

    /// <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 readonly 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 IWordWindow 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) {
            var buf = new StringBuilder(128);
            GetClassName(hwndChild, buf, 128);
            Console.WriteLine(buf.ToString());

            if (buf.ToString() == "_WwG") { 
                lParam = hwndChild;
                return false;
            }
            return true;
        }

        static void 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:
            // int hwnd = (int)Process.GetProcessById(excelPid).MainWindowHandle;
            // var p=Process.GetProcesses().FirstOrDefault(x => x.ProcessName=="WINWORD");
            var hwnd = (int) FindWindow("OpusApp", null);

            if (hwnd == 0) 
                throw new Exception("Can't find Word");

            // Search the accessible child window (it has class name "_WwG") // http://msdn.microsoft.com/en-us/library/windows/desktop/dd317978%28v=vs.85%29.aspx
            var hwndChild = 0;
            var cb = new EnumChildCallback(EnumChildProc);
            EnumChildWindows(hwnd, cb, ref hwndChild);

            if (hwndChild == 0) 
                throw new Exception("Can't find Automation Child Window");

            // 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;
            var IID_IDispatch = new Guid("{00020400-0000-0000-C000-000000000046}");
            IWordWindow ptr;

            var hr = AccessibleObjectFromWindow(hwndChild, OBJID_NATIVEOM, IID_IDispatch.ToByteArray(), out ptr);

            if (hr < 0) 
                throw new Exception("Can't get Accessible Object");

            // 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 (new UiLanguageHelper()) {
                var wordApp = ptr.GetType().InvokeMember("Application", BindingFlags.GetProperty, null, ptr, null);

                var version = wordApp.GetType().InvokeMember("Version", BindingFlags.GetField | BindingFlags.InvokeMethod | BindingFlags.GetProperty, null, wordApp, null);
                Console.WriteLine("Word version is: {0}", version);

                dynamic wordAppd = ptr.GetType().InvokeMember("Application", BindingFlags.GetProperty, null, ptr, null);
                Console.WriteLine("Version: " + wordAppd.Version);
            }
        }
    }
}

Answer 4

不。

我知道这听起来很陈词滥调，但在使用 Excel 时，VB 比 C# 更容易使用很多很多倍。 即使您使用 PIA 而不是全部后期绑定，您仍然最好使用 VB。

（注意：当 C# 4 发布时，所有这些评论都会立即出错。）