剪贴板更改通知？

Question

我知道如何将内容放入剪贴板以及如何从剪贴板检索内容。

但是，在这两个操作之间，另一个操作可能会更改剪贴板的内容。

有没有办法在任何应用程序修改剪贴板时收到通知？

Answer 1

您需要添加的唯一参考是 wpf 应用程序中的 Windows 窗体。我为我在互联网上找到的功能创建了一个包装器。

大多数示例所做的事情超出了我的需要，因此我决定创建自己的类。我喜欢隔离问题，因此此类仅在剪贴板更改时进行监听，并告诉您剪贴板上的数据类型。例如它是文本吗？一个图像？或者什么？

无论如何，这是我的包装：

using System;
using System.Windows.Forms;
using System.Threading;
using System.Runtime.InteropServices;

public static class ClipboardMonitor 
{
    public delegate void OnClipboardChangeEventHandler(ClipboardFormat format, object data);
    public static event OnClipboardChangeEventHandler OnClipboardChange;

    public static void Start()
    {
        ClipboardWatcher.Start();
        ClipboardWatcher.OnClipboardChange += (ClipboardFormat format, object data) =>
        {
            if (OnClipboardChange != null)
                OnClipboardChange(format, data);
        };
    }

    public static void Stop()
    {
        OnClipboardChange = null;
        ClipboardWatcher.Stop();
    }
    
    class ClipboardWatcher : Form
    {
        // static instance of this form
        private static ClipboardWatcher mInstance;

        // needed to dispose this form
        static IntPtr nextClipboardViewer;

        public delegate void OnClipboardChangeEventHandler(ClipboardFormat format, object data);
        public static event OnClipboardChangeEventHandler OnClipboardChange;

        // start listening
        public static void Start()
        {
            // we can only have one instance if this class
            if (mInstance != null)
                return;

            Thread t = new Thread(new ParameterizedThreadStart(x =>
            {
                Application.Run(new ClipboardWatcher());
            }));
            t.SetApartmentState(ApartmentState.STA); // give the [STAThread] attribute
            t.Start();
        }

        // stop listening (dispose form)
        public static void Stop()
        {
            mInstance.Invoke(new MethodInvoker(() =>
            {
                ChangeClipboardChain(mInstance.Handle, nextClipboardViewer);
            }));
            mInstance.Invoke(new MethodInvoker(mInstance.Close));

            mInstance.Dispose();

            mInstance = null;
        }

        // on load: (hide this window)
        protected override void SetVisibleCore(bool value)
        {
            CreateHandle();

            mInstance = this;

            nextClipboardViewer = SetClipboardViewer(mInstance.Handle);

            base.SetVisibleCore(false);
        }

        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr SetClipboardViewer(IntPtr hWndNewViewer);

        [DllImport("User32.dll", CharSet = CharSet.Auto)]
        public static extern bool ChangeClipboardChain(IntPtr hWndRemove, IntPtr hWndNewNext);

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern int SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, IntPtr lParam);

        // defined in winuser.h
        const int WM_DRAWCLIPBOARD = 0x308;
        const int WM_CHANGECBCHAIN = 0x030D;

        protected override void WndProc(ref Message m)
        {
            switch (m.Msg)
            {
                case WM_DRAWCLIPBOARD:
                    ClipChanged();
                    SendMessage(nextClipboardViewer, m.Msg, m.WParam, m.LParam);
                    break;

                case WM_CHANGECBCHAIN:
                    if (m.WParam == nextClipboardViewer)
                        nextClipboardViewer = m.LParam;
                    else
                        SendMessage(nextClipboardViewer, m.Msg, m.WParam, m.LParam);
                    break;

                default:
                    base.WndProc(ref m);
                    break;
            }
        }

        static readonly string[] formats = Enum.GetNames(typeof(ClipboardFormat));

        private void ClipChanged()
        {
            IDataObject iData = Clipboard.GetDataObject();

            ClipboardFormat? format = null;

            foreach (var f in formats)
            {
                if (iData.GetDataPresent(f))
                {
                    format = (ClipboardFormat)Enum.Parse(typeof(ClipboardFormat), f);
                    break;
                }
            }

            object data = iData.GetData(format.ToString());

            if (data == null || format == null)
                return;

            if (OnClipboardChange != null)
                OnClipboardChange((ClipboardFormat)format, data);
        }


    }
}

public enum ClipboardFormat : byte
{
    /// <summary>Specifies the standard ANSI text format. This static field is read-only.
    /// </summary>
    /// <filterpriority>1</filterpriority>
    Text,
    /// <summary>Specifies the standard Windows Unicode text format. This static field
    /// is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    UnicodeText,
    /// <summary>Specifies the Windows device-independent bitmap (DIB) format. This static
    /// field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Dib,
    /// <summary>Specifies a Windows bitmap format. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Bitmap,
    /// <summary>Specifies the Windows enhanced metafile format. This static field is
    /// read-only.</summary>
    /// <filterpriority>1</filterpriority>
    EnhancedMetafile,
    /// <summary>Specifies the Windows metafile format, which Windows Forms does not
    /// directly use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    MetafilePict,
    /// <summary>Specifies the Windows symbolic link format, which Windows Forms does
    /// not directly use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    SymbolicLink,
    /// <summary>Specifies the Windows Data Interchange Format (DIF), which Windows Forms
    /// does not directly use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Dif,
    /// <summary>Specifies the Tagged Image File Format (TIFF), which Windows Forms does
    /// not directly use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Tiff,
    /// <summary>Specifies the standard Windows original equipment manufacturer (OEM)
    /// text format. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    OemText,
    /// <summary>Specifies the Windows palette format. This static field is read-only.
    /// </summary>
    /// <filterpriority>1</filterpriority>
    Palette,
    /// <summary>Specifies the Windows pen data format, which consists of pen strokes
    /// for handwriting software, Windows Forms does not use this format. This static
    /// field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    PenData,
    /// <summary>Specifies the Resource Interchange File Format (RIFF) audio format,
    /// which Windows Forms does not directly use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Riff,
    /// <summary>Specifies the wave audio format, which Windows Forms does not directly
    /// use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    WaveAudio,
    /// <summary>Specifies the Windows file drop format, which Windows Forms does not
    /// directly use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    FileDrop,
    /// <summary>Specifies the Windows culture format, which Windows Forms does not directly
    /// use. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Locale,
    /// <summary>Specifies text consisting of HTML data. This static field is read-only.
    /// </summary>
    /// <filterpriority>1</filterpriority>
    Html,
    /// <summary>Specifies text consisting of Rich Text Format (RTF) data. This static
    /// field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Rtf,
    /// <summary>Specifies a comma-separated value (CSV) format, which is a common interchange
    /// format used by spreadsheets. This format is not used directly by Windows Forms.
    /// This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    CommaSeparatedValue,
    /// <summary>Specifies the Windows Forms string class format, which Windows Forms
    /// uses to store string objects. This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    StringFormat,
    /// <summary>Specifies a format that encapsulates any type of Windows Forms object.
    /// This static field is read-only.</summary>
    /// <filterpriority>1</filterpriority>
    Serializable,
}

我知道它可能太多了，但包装后它应该看起来像：

然后将该类用作：

    static void Main(string[] args)
    {

        ClipboardMonitor.Start();

        ClipboardMonitor.OnClipboardChange += new ClipboardMonitor.OnClipboardChangeEventHandler(ClipboardMonitor_OnClipboardChange);

        Console.Read();

        ClipboardMonitor.Stop(); // do not forget to stop


        
    }

    static void ClipboardMonitor_OnClipboardChange(ClipboardFormat format, object data)
    {
        Console.WriteLine("Clipboard changed and it has the format: "+format.ToString());
    }

Answer 2

我能找到的只是一个用 C#/VB.NET 编写的 剪贴板监视器。我看到了 WPF 和 WinForms，所以我假设这是一个可行的选择。

涉及 pinvoking user32 dll 中的一些方法。

编辑

在编辑时，上面的原始链接已损坏。这是 archive.org 快照

Answer 3

但是，在这两个操作之间，还可以进行另一个操作
更改剪贴板内容的操作。

当应用程序调用 OpenClipboard() 时，其他应用程序不能使用剪贴板。一旦锁定剪贴板的应用程序调用 CloseClipboard()，任何应用程序都可以使用并锁定剪贴板。

当任何应用程序修改
剪贴板？

是的。请参阅 API SetClipboardViewer() 以及消息 WM_DRAWCLIPBOARD 和 WM_CHANGECBCHAIN。

更多信息请参见：http://msdn.microsoft.com/en-us/library/ms649016(v=vs.85).aspx#_win32_Adding_a_Window_to_the_Clipboard_Viewer_Chain

Answer 4

这是我几年前写的一篇文章，详细介绍了剪贴板甚至通过 Windows API 进行监控：
http://www.clipboardextender.com/developing-clipboard-aware -programs-for-windows/6
请特别注意“常见错误”部分。几乎没有人第一次就能正确地做到这一点。