如何获得活动的Excel实例？
我有一个应用程序在C＃中，这个应用程序粘贴信息，以满足用户的需求，后面的逻辑是这样的，如果没有运行的Excel实例，它创build一个并粘贴到该实例。
如果只有一个实例在运行，它将尝试获取该实例并使用它。 这是我正在使用的代码：
Guid _guid; CLSIDFromProgID("Excel.Application", out _guid); if (_guid == Guid.Empty) {...} IntPtr _ptr = new IntPtr(); GetActiveObject(ref _guid, _ptr, out objApp); 到目前为止，每一个工作都可以正常工作，但是我所遇到的问题是，当有多个excel实例运行时，我想要获取Excel的活动实例，但是目前我只能打开第一个实例，是根据我读到的在运行对象表中注册的第一个实例。
有没有办法“问”到Excel实例，如果它是活动的实例，并因此使用它？ 或者我如何获得活动实例？
对于所有的可能性来获得或开始Excel看到这个博客文章安德鲁怀特佩尔：
以编程方式启动Office应用程序
如果您可以获得“活动”Excel实例的窗口句柄，则可能需要尝试使用AccessibleObjectFromWindow ，以便您访问OM。
我创build了一个类，可以遍历所有正在运行的Excel实例，并通过Hwnd，ProcessID或Process对象进行查找。 它还有一个属性，用于返回双击Excel文件图标的实例的“Active”实例（根据Marshal类）以及最顶层的实例，即顶层实例几乎窗口。
下面的代码，但检查此链接进一步的描述。
http://www.codeproject.com/Tips/1080611/Get-a-Collection-of-All-Running-Excel-Instances
这尚未在所有版本的Excel或Windows上进行testing。
码：
using System; using System.Collections; using System.Collections.Generic; using System.Diagnostics; using System.Linq; using System.Runtime.InteropServices; //Don't add the entire interop namespace, it will introduce some naming conflicts. using xlApp = Microsoft.Office.Interop.Excel.Application; using xlWin = Microsoft.Office.Interop.Excel.Window; namespace ExcelExtensions { /// <summary> /// Collection of currently running Excel instances. /// </summary> public class ExcelAppCollection : IEnumerable<xlApp> { #region Constructors /// <summary>Initializes a new instance of the /// <see cref="ExcelAppCollection"/> class.</summary> /// <param name="sessionID">Windows sessionID to filter instances by. /// If not assigned, uses current session.</param> public ExcelAppCollection (Int32? sessionID = null) { if (sessionID.HasValue && sessionID.Value < -1) throw new ArgumentOutOfRangeException("sessionID"); this.SessionID = sessionID ?? Process.GetCurrentProcess().SessionId; } #endregion #region Properties /// <summary>Gets the Windows sessionID used to filter instances. /// If -1, uses instances from all sessions.</summary> /// <value>The sessionID.</value> public Int32 SessionID { get; private set; } #endregion #region Accessors /// <summary>Gets the Application associated with a given process.</summary> /// <param name="process">The process.</param> /// <returns>Application associated with process.</returns> /// <exception cref="System.ArgumentNullException">process</exception> public xlApp FromProcess(Process process) { if (process == null) throw new ArgumentNullException("process"); return InnerFromProcess(process); } /// <summary>Gets the Application associated with a given processID.</summary> /// <param name="processID">The process identifier.</param> /// <returns>Application associated with processID.</returns> public xlApp FromProcessID(Int32 processID) { try { return FromProcess(Process.GetProcessById(processID)); } catch (ArgumentException) { return null; } } /// <summary>Get the Application associated with a given window handle.</summary> /// <param name="mainHandle">The window handle.</param> /// <returns>Application associated with window handle.</returns> public xlApp FromMainWindowHandle(Int32 mainHandle) { return InnerFromHandle(ChildHandleFromMainHandle(mainHandle)); } /// <summary>Gets the main instance. </summary> /// <remarks>This is the oldest running instance. /// It will be used if an Excel file is double-clicked in Explorer, etc.</remarks> public xlApp PrimaryInstance { get { try { return Marshal.GetActiveObject(MarshalName) as xlApp; } catch (COMException) { return null; } } } /// <summary>Gets the top most instance.</summary> /// <value>The top most instance.</value> public xlApp TopMostInstance { get { var topMost = GetProcesses() //All Excel processes .Select(p => p.MainWindowHandle) //All Excel main window handles .Select(h => new { h = h, z = GetWindowZ(h) }) //Get (handle, z) pair per instance .Where(x => xz > 0) //Filter hidden instances .OrderBy(x => xz) //Sort by z value .First(); //Lowest z value return FromMainWindowHandle(topMost.h.ToInt32()); } } #endregion #region Methods /// <summary>Returns an enumerator that iterates through the collection.</summary> /// <returns> /// A <see cref="T:System.Collections.Generic.IEnumerator`1" /> /// that can be used to iterate through the collection. /// </returns> public IEnumerator<xlApp> GetEnumerator() { foreach (var p in GetProcesses()) yield return FromProcess(p); } IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); } /// <summary>Gets all Excel processes in the current session.</summary> /// <returns>Collection of all Excel processing in the current session.</returns> public IEnumerable<Process> GetProcesses() { IEnumerable<Process> result = Process.GetProcessesByName(ProcessName); if (this.SessionID >= 0) result = result.Where(p => p.SessionId == SessionID); return result; } #endregion //--------Implementation #region Methods private static xlApp InnerFromProcess(Process p) { return InnerFromHandle(ChildHandleFromMainHandle(p.MainWindowHandle.ToInt32())); } private static Int32 ChildHandleFromMainHandle(Int32 mainHandle) { Int32 handle = 0; EnumChildWindows(mainHandle, EnumChildFunc, ref handle); return handle; } private static xlApp InnerFromHandle(Int32 handle) { xlWin win = null; Int32 hr = AccessibleObjectFromWindow(handle, DW_OBJECTID, rrid.ToByteArray(), ref win); return win.Application; } private static Int32 GetWindowZ(IntPtr handle) { var z = 0; for (IntPtr h = handle; h != IntPtr.Zero; h = GetWindow(h, GW_HWNDPREV)) z++; return z; } private static Boolean EnumChildFunc(Int32 hwndChild, ref Int32 lParam) { var buf = new StringBuilder(128); GetClassName(hwndChild, buf, 128); if (buf.ToString() == ComClassName) { lParam = hwndChild; return false; } return true; } #endregion #region Extern Methods [DllImport("Oleacc.dll")] private static extern Int32 AccessibleObjectFromWindow( Int32 hwnd, UInt32 dwObjectID, Byte[] riid, ref xlWin ptr); [DllImport("User32.dll")] private static extern Boolean EnumChildWindows( Int32 hWndParent, EnumChildCallback lpEnumFunc, ref Int32 lParam); [DllImport("User32.dll")] private static extern Int32 GetClassName( Int32 hWnd, StringBuilder lpClassName, Int32 nMaxCount); [DllImport("User32.dll")] private static extern IntPtr GetWindow(IntPtr hWnd, UInt32 uCmd); #endregion #region Constants & delegates private const String MarshalName = "Excel.Application"; private const String ProcessName = "EXCEL"; private const String ComClassName = "EXCEL7"; private const UInt32 DW_OBJECTID = 0xFFFFFFF0; private const UInt32 GW_HWNDPREV = 3; //3 = GW_HWNDPREV //The retrieved handle identifies the window above the specified window in the Z order. //If the specified window is a topmost window, the handle identifies a topmost window. //If the specified window is a top-level window, the handle identifies a top-level window. //If the specified window is a child window, the handle identifies a sibling window. private static Guid rrid = new Guid("{00020400-0000-0000-C000-000000000046}"); private delegate Boolean EnumChildCallback(Int32 hwnd, ref Int32 lParam); #endregion } }