Clipboard.GetText返回null(空字符串)

我的剪贴板填充了文本,但是当我运行时

string clipboardData = Clipboard.GetText(System.Windows.Forms.TextDataFormat.Text);

我找回一个空字符串.我玩过各种形式的电话,包括:

string clipboardData = Clipboard.GetText();
string clipboardData = Clipboard.GetText(System.Windows.Forms.TextDataFormat.UnicodeText);

但结果相同.

我错过了一些明显的东西吗

1> BoltBait..：

---

您只能从STA线程访问剪贴板.Rick Brewster在Paint.NET中对常规的Edit-> Paste命令进行了一些重构.

码:

IDataObject idat = null;
Exception threadEx = null;
Thread staThread = new Thread(
    delegate ()
    {
        try
        {
            idat = Clipboard.GetDataObject();
        }

        catch (Exception ex) 
        {
            threadEx = ex;            
        }
    });
staThread.SetApartmentState(ApartmentState.STA);
staThread.Start();
staThread.Join();
// at this point either you have clipboard data or an exception

代码来自里克.http://forums.getpaint.net/index.php?/topic/13712-/page__view__findpost__p__226140

更新:Jason Heine()在delegate修复模糊方法错误之后提出了一个很好的补充点.

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不确定其他框架,但在.net 4.0委托之后需要有(),否则会出现模糊的方法错误.

2> Danilo Barge..：

---

老实说,我不知道STA线程是什么,但在简单的项目中,它可以解决[STAThread]在Main方法之前添加的问题:

[STAThread]
static void Main(string[] args)
{ (...)

它对我有用,所以我不会质疑这个方法;)

---

关于[STAThread]装饰器的更多信息在博客文章中为什么需要STAThread？.

---

哦，天哪，这帮助了我很多！非常感谢！

3> Braian Bress..：

---

我已经编写了这个类,它可以工作,并且做同样的事情,只需添加你需要的方法就可以轻松改进

    Private Class ClipboardAsync

    Private _GetText As String
    Private Sub _thGetText(ByVal format As Object)
        Try
            If format Is Nothing Then
                _GetText = Clipboard.GetText()
            Else
                _GetText = Clipboard.GetText(DirectCast(format, TextDataFormat))
            End If

        Catch ex As Exception
            _GetText = String.Empty
        End Try
    End Sub
    Public Function GetText() As String
        Dim instance As New ClipboardAsync
        Dim staThread As New Thread(AddressOf instance._thGetText)
        staThread.SetApartmentState(ApartmentState.STA)
        staThread.Start()
        staThread.Join()
        Return instance._GetText
    End Function
    Public Function GetText(ByVal format As TextDataFormat) As String
        Dim instance As New ClipboardAsync
        Dim staThread As New Thread(AddressOf instance._thGetText)
        staThread.SetApartmentState(ApartmentState.STA)
        staThread.Start(format)
        staThread.Join()
        Return instance._GetText
    End Function

    Private _ContainsText As Boolean
    Private Sub _thContainsText(ByVal format As Object)
        Try
            If format Is Nothing Then
                _ContainsText = Clipboard.ContainsText()
            Else
                _ContainsText = Clipboard.ContainsText(DirectCast(format, TextDataFormat))
            End If
        Catch ex As Exception
            _ContainsText = False
        End Try
    End Sub
    Public Function ContainsText() As Boolean
        Dim instance As New ClipboardAsync
        Dim staThread As New Thread(AddressOf instance._thContainsFileDropList)
        staThread.SetApartmentState(ApartmentState.STA)
        staThread.Start()
        staThread.Join()
        Return instance._ContainsText
    End Function
    Public Function ContainsText(ByVal format As Object) As Boolean
        Dim instance As New ClipboardAsync
        Dim staThread As New Thread(AddressOf instance._thContainsFileDropList)
        staThread.SetApartmentState(ApartmentState.STA)
        staThread.Start(format)
        staThread.Join()
        Return instance._ContainsText
    End Function

    Private _ContainsFileDropList As Boolean
    Private Sub _thContainsFileDropList(ByVal format As Object)
        Try
            _ContainsFileDropList = Clipboard.ContainsFileDropList
        Catch ex As Exception
            _ContainsFileDropList = False
        End Try
    End Sub
    Public Function ContainsFileDropList() As Boolean
        Dim instance As New ClipboardAsync
        Dim staThread As New Thread(AddressOf instance._thContainsFileDropList)
        staThread.SetApartmentState(ApartmentState.STA)
        staThread.Start()
        staThread.Join()
        Return instance._ContainsFileDropList
    End Function

    Private _GetFileDropList As Specialized.StringCollection
    Private Sub _thGetFileDropList()
        Try
            _GetFileDropList = Clipboard.GetFileDropList
        Catch ex As Exception
            _GetFileDropList = Nothing
        End Try
    End Sub
    Public Function GetFileDropList() As Specialized.StringCollection
        Dim instance As New ClipboardAsync
        Dim staThread As New Thread(AddressOf instance._thGetFileDropList)
        staThread.SetApartmentState(ApartmentState.STA)
        staThread.Start()
        staThread.Join()
        Return instance._GetFileDropList
    End Function
End Class

这是CSharp版本:

private class ClipboardAsync
{

private string _GetText;
private void _thGetText(object format)
{
    try {
        if (format == null) {
            _GetText = Clipboard.GetText();
        }
        else {
            _GetText = Clipboard.GetText((TextDataFormat)format);

        }
    }
    catch (Exception ex) {
        //Throw ex 
        _GetText = string.Empty;
    }
}
public string GetText()
{
    ClipboardAsync instance = new ClipboardAsync();
    Thread staThread = new Thread(instance._thGetText);
    staThread.SetApartmentState(ApartmentState.STA);
    staThread.Start();
    staThread.Join();
    return instance._GetText;
}
public string GetText(TextDataFormat format)
{
    ClipboardAsync instance = new ClipboardAsync();
    Thread staThread = new Thread(instance._thGetText);
    staThread.SetApartmentState(ApartmentState.STA);
    staThread.Start(format);
    staThread.Join();
    return instance._GetText;
}

private bool _ContainsText;
private void _thContainsText(object format)
{
    try {
        if (format == null) {
            _ContainsText = Clipboard.ContainsText();
        }
        else {
            _ContainsText = Clipboard.ContainsText((TextDataFormat)format);
        }
    }
    catch (Exception ex) {
        //Throw ex 
        _ContainsText = false;
    }
}
public bool ContainsText()
{
    ClipboardAsync instance = new ClipboardAsync();
    Thread staThread = new Thread(instance._thContainsFileDropList);
    staThread.SetApartmentState(ApartmentState.STA);
    staThread.Start();
    staThread.Join();
    return instance._ContainsText;
}
public bool ContainsText(object format)
{
    ClipboardAsync instance = new ClipboardAsync();
    Thread staThread = new Thread(instance._thContainsFileDropList);
    staThread.SetApartmentState(ApartmentState.STA);
    staThread.Start(format);
    staThread.Join();
    return instance._ContainsText;
}

private bool _ContainsFileDropList;
private void _thContainsFileDropList(object format)
{
    try {
        _ContainsFileDropList = Clipboard.ContainsFileDropList;
    }
    catch (Exception ex) {
        //Throw ex 
        _ContainsFileDropList = false;
    }
}
public bool ContainsFileDropList()
{
    ClipboardAsync instance = new ClipboardAsync();
    Thread staThread = new Thread(instance._thContainsFileDropList);
    staThread.SetApartmentState(ApartmentState.STA);
    staThread.Start();
    staThread.Join();
    return instance._ContainsFileDropList;
}

private Specialized.StringCollection _GetFileDropList;
private void _thGetFileDropList()
{
    try {
        _GetFileDropList = Clipboard.GetFileDropList;
    }
    catch (Exception ex) {
        //Throw ex 
        _GetFileDropList = null;
    }
}
public Specialized.StringCollection GetFileDropList()
{
    ClipboardAsync instance = new ClipboardAsync();
    Thread staThread = new Thread(instance._thGetFileDropList);
    staThread.SetApartmentState(ApartmentState.STA);
    staThread.Start();
    staThread.Join();
    return instance._GetFileDropList;
}
}

你可以简单地使用它:Vb.net:

Dim Clipboard2 As New ClipboardAsync
MessageBox.Show (Clipboard2.ContainsText())

CSHARP:

ClipboardAsync Clipboard2 = new ClipboardAsync();
MessageBox.Show (Clipboard2.ContainsText());

4> 小智..：

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BoltBait的代码不适用于IDataObject,因为数据对象丢失了线程外的信息.一切正常,如果IDataObject只在线程内使用,如下所示:

IDataObject idat = null;
Exception threadEx = null;
String text = "";
Thread staThread = new Thread(
    delegate ()
    {
        try
        {
            idat = Clipboard.GetDataObject();
            text = idat.GetData(DataFormats.Text)
        }

        catch (Exception ex) 
        {
            threadEx = ex;            
        }
    });
staThread.SetApartmentState(ApartmentState.STA);
staThread.Start();
staThread.Join();
// here you can use text, which contains data from clipboard