C# 如何在非主线程中获取剪贴板数据?
我试图用下面的代码从剪贴板中获取数据C# 如何在非主线程中获取剪贴板数据?,c#,multithreading,winforms,clipboard,C#,Multithreading,Winforms,Clipboard,我试图用下面的代码从剪贴板中获取数据 private void TestBtn_Click(object sender, EventArgs e) { Thread sampleThread = new Thread(SampleMethod); sampleThread.IsBackground = true; sampleThread.Start(); Thread.Sleep(2000); var textFromMain = Clipboard.GetText(TextData
private void TestBtn_Click(object sender, EventArgs e)
{
Thread sampleThread = new Thread(SampleMethod);
sampleThread.IsBackground = true;
sampleThread.Start();
Thread.Sleep(2000);
var textFromMain = Clipboard.GetText(TextDataFormat.Text);
}
private void SampleMethod()
{
var textFromThread = Clipboard.GetText(TextDataFormat.Text);
Thread.Sleep(1000);
}
我用这行代码将任何文本复制到剪贴板-
var textFromMain=Clipboard.GetText(TextDataFormat.Text)代码>
但下面的行返回空字符串或空字符串
var textFromThread=Clipboard.GetText(TextDataFormat.Text)代码>
我不明白问题出在哪里。有人能帮我理解吗。如果是多线程的,请告诉我正确的方向 Clipboard.GetText(TextDataFormat.Text)使用COM并在未标记STAThreadAttribute的线程中调用时引发异常
解决此问题的一种方法是使用委托将Clipboard.GetText的调用返回到带有Invoke的主线程。但在这种情况下,线程将在调用时冻结它的执行,直到SampleMethod()在主窗体线程上结束它的执行,主线程将被释放
另一种方法是使用自己对COM的调用来获取剪贴板文本,而不是System.Windows.Forms.clipboard.GetText(),请参阅ClipboardCom.GetText(),此方法不需要等待主窗体线程
private string _textFromMain, _textFromThreadByInvoke, _textFromThreadByCom;
private delegate string GetClipboardInvoke(TextDataFormat textformat);
private void SampleInvokeMethod()
{
GetClipboardInvoke invokerClipboard = new GetClipboardInvoke(Clipboard.GetText);
_textFromThreadByInvoke = (string)this.Invoke(invokerClipboard, TextDataFormat.Text); // where this is a Form
Thread.Sleep(1000);
}
private void button1_Click(object sender, EventArgs e)
{
Thread sampleInvokeThread = new Thread(SampleInvokeMethod) { IsBackground = true };
sampleInvokeThread.Start();
Thread sampleComThread = new Thread(SampleComMethod) { IsBackground = true };
sampleComThread.Start();
Thread.Sleep(10000);
_textFromMain = Clipboard.GetText(TextDataFormat.Text);
}
private void SampleComMethod()
{
_textFromThreadByCom = ClipboardCom.GetText();
Thread.Sleep(1000);
}
public static class ClipboardCom
{
[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;
}
}
GetText(TextDataFormat.Text)使用COM并在未标记STAThreadAttribute的线程中调用时引发异常
解决此问题的一种方法是使用委托将Clipboard.GetText的调用返回到带有Invoke的主线程。但在这种情况下,线程将在调用时冻结它的执行,直到SampleMethod()在主窗体线程上结束它的执行,主线程将被释放
另一种方法是使用自己对COM的调用来获取剪贴板文本,而不是System.Windows.Forms.clipboard.GetText(),请参阅ClipboardCom.GetText(),此方法不需要等待主窗体线程
private string _textFromMain, _textFromThreadByInvoke, _textFromThreadByCom;
private delegate string GetClipboardInvoke(TextDataFormat textformat);
private void SampleInvokeMethod()
{
GetClipboardInvoke invokerClipboard = new GetClipboardInvoke(Clipboard.GetText);
_textFromThreadByInvoke = (string)this.Invoke(invokerClipboard, TextDataFormat.Text); // where this is a Form
Thread.Sleep(1000);
}
private void button1_Click(object sender, EventArgs e)
{
Thread sampleInvokeThread = new Thread(SampleInvokeMethod) { IsBackground = true };
sampleInvokeThread.Start();
Thread sampleComThread = new Thread(SampleComMethod) { IsBackground = true };
sampleComThread.Start();
Thread.Sleep(10000);
_textFromMain = Clipboard.GetText(TextDataFormat.Text);
}
private void SampleComMethod()
{
_textFromThreadByCom = ClipboardCom.GetText();
Thread.Sleep(1000);
}
public static class ClipboardCom
{
[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;
}
}
我最后使用下面的方法访问剪贴板文本
private string GetClipBoradData()
{
try
{
string clipboardData= null;
Exception threadEx = null;
Thread staThread = new Thread(
delegate ()
{
try
{
clipboardData= Clipboard.GetText(TextDataFormat.Text);
}
catch (Exception ex)
{
threadEx = ex;
}
});
staThread.SetApartmentState(ApartmentState.STA);
staThread.Start();
staThread.Join();
return clipboardData;
}
catch (Exception exception)
{
return string.Empty;
}
}
我最后使用下面的方法访问剪贴板文本
private string GetClipBoradData()
{
try
{
string clipboardData= null;
Exception threadEx = null;
Thread staThread = new Thread(
delegate ()
{
try
{
clipboardData= Clipboard.GetText(TextDataFormat.Text);
}
catch (Exception ex)
{
threadEx = ex;
}
});
staThread.SetApartmentState(ApartmentState.STA);
staThread.Start();
staThread.Join();
return clipboardData;
}
catch (Exception exception)
{
return string.Empty;
}
}
下面的代码适用于我
Thread theThread = new Thread((ThreadStart)delegate
{
var selectedPodcastPlaylist = (PodcastPlaylist)metroGridPodcastPlaylist.SelectedRows[0].DataBoundItem;
Clipboard.SetText(selectedPodcastPlaylist.URI);
});
try
{
//set STA as the Open file dialog needs it to work
theThread.TrySetApartmentState(ApartmentState.STA);
//start the thread
theThread.Start();
// Wait for thread to get started
while (!theThread.IsAlive) { Thread.Sleep(1); }
// Wait a tick more (@see: http://scn.sap.com/thread/45710)
Thread.Sleep(1);
//wait for the dialog thread to finish
theThread.Join();
}
catch (Exception)
{
}
灵感来源于本文和本文来源
以下代码适用于我
Thread theThread = new Thread((ThreadStart)delegate
{
var selectedPodcastPlaylist = (PodcastPlaylist)metroGridPodcastPlaylist.SelectedRows[0].DataBoundItem;
Clipboard.SetText(selectedPodcastPlaylist.URI);
});
try
{
//set STA as the Open file dialog needs it to work
theThread.TrySetApartmentState(ApartmentState.STA);
//start the thread
theThread.Start();
// Wait for thread to get started
while (!theThread.IsAlive) { Thread.Sleep(1); }
// Wait a tick more (@see: http://scn.sap.com/thread/45710)
Thread.Sleep(1);
//wait for the dialog thread to finish
theThread.Join();
}
catch (Exception)
{
}
灵感来源于本文和本文来源
谢谢你的帮助,但我最后选择了另一条捷径。将它添加到答案中。谢谢您的帮助,但我最终选择了另一个较短的方法。将它添加到答案中。