C# Clipboard.GetText()

问题:

How can I get the clipboard text in a non static thread? I have a solution but I'm trying to get the cleanest/shortest way possible. The results turn up as an empty string when calling it normally.

回答1:

I would add a helper method that can run an Action as an STA Thread within a MTA Main Thread. I think that is probably the cleanest way to achive it.

class Program
{
    [MTAThread]
    static void Main(string[] args)
    {
        RunAsSTAThread(
            () =>
            {
                Clipboard.SetText("Hallo");
                Console.WriteLine(Clipboard.GetText());
            });
    }

    /// <summary>
    /// Start an Action within an STA Thread
    /// </summary>
    /// <param name="goForIt"></param>
    static void RunAsSTAThread(Action goForIt)
    {
        AutoResetEvent @event = new AutoResetEvent(false);
        Thread thread = new Thread(
            () =>
            {
                goForIt();
                @event.Set();
            });
        thread.SetApartmentState(ApartmentState.STA);
        thread.Start();
        @event.WaitOne();
    }
}

回答2:

try adding the ApartmentStateAttribute to your main method

[STAThread]
static void Main() {
  //my beautiful codes
}

回答3:

I don't know what your definitions of clean or short are, but if you're willing to use full trust, you can just P/Invoke the native clipboard functions to avoid the threading issues. Here's a complete program to print the text on the clipboard:

using System;
using System.Runtime.InteropServices;

namespace PasteText
{
    public static class Clipboard
    {
        [DllImport("user32.dll")]
        static extern IntPtr GetClipboardData(uint uFormat);
        [DllImport("user32.dll")]
        static extern bool IsClipboardFormatAvailable(uint format);
        [DllImport("user32.dll", SetLastError = true)]
        static extern bool OpenClipboard(IntPtr hWndNewOwner);
        [DllImport("user32.dll", SetLastError = true)]
        static extern bool CloseClipboard();
        [DllImport("kernel32.dll")]
        static extern IntPtr GlobalLock(IntPtr hMem);
        [DllImport("kernel32.dll")]
        static extern bool GlobalUnlock(IntPtr hMem);

        const uint CF_UNICODETEXT = 13;

        public static string GetText()
        {
            if (!IsClipboardFormatAvailable(CF_UNICODETEXT))
                return null;
            if (!OpenClipboard(IntPtr.Zero))
                return null;

            string data = null;
            var hGlobal = GetClipboardData(CF_UNICODETEXT);
            if (hGlobal != IntPtr.Zero)
            {
                var lpwcstr = GlobalLock(hGlobal);
                if (lpwcstr != IntPtr.Zero)
                {
                    data = Marshal.PtrToStringUni(lpwcstr);
                    GlobalUnlock(lpwcstr);
                }
            }
            CloseClipboard();

            return data;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(Clipboard.GetText());
        }
    }
}

回答4:

You can't; you must specify the STAThread attribute.

Note:

ThreadStateException

The current thread is not in single-threaded apartment (STA) mode. Add the STAThreadAttribute to your application's Main method.