c# - 剪贴板监视器

Question

我有一个问题。我正在尝试为我的 C# 应用程序使用 ClipboardMonitor。目标是监视剪贴板中的每个更改。开始监控:

AddClipboardFormatListener(this.Handle);

停止监听器:

RemoveClipboardFormatListener(this.Handle);

以及覆盖 WndProc() 方法:

const int WM_DRAWCLIPBOARD = 0x308;
const int WM_CHANGECBCHAIN = 0x030D;

protected override void WndProc(ref Message m)
{
    switch (m.Msg)
    {
        case WM_DRAWCLIPBOARD:
            IDataObject iData = Clipboard.GetDataObject();
            if (iData.GetDataPresent(DataFormats.Text))
            {
                ClipboardMonitor_OnClipboardChange((string)iData.GetData(DataFormats.Text));
            }
            break;

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

当然还有 DLL 导入:

[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool AddClipboardFormatListener(IntPtr hwnd);

[DllImport("user32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool RemoveClipboardFormatListener(IntPtr hwnd);

但是当在方法调用处放置断点 ClipboardMonitor_OnClipboardChange 并更改剪贴板时，我从未调用过该方法。

如何更改我的代码以便收到 WM_ 消息通知我剪贴板已更改？

Answer 1

问题是您正在处理错误的窗口消息。引用 AddClipboardFormatListener 的文档:

When a window has been added to the clipboard format listener list, it is posted a WM_CLIPBOARDUPDATE message whenever the contents of the clipboard have changed.

根据这些知识，将代码更改为:

const int WM_CLIPBOARDUPDATE = 0x031D;
protected override void WndProc(ref Message m)
{
    switch (m.Msg)
    {
        case WM_CLIPBOARDUPDATE:
            IDataObject iData = Clipboard.GetDataObject();
            if (iData.GetDataPresent(DataFormats.Text))
            {
                string data = (string)iData.GetData(DataFormats.Text);
            }
            break;


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