“Current thread must be set to single thread apartment (STA)” error in copy string to clipboard

Question

I have tried code from How to copy data to clipboard in C#:

Clipboard.SetText(\"Test!\");

And I get this error:

Curr

Answer 1

You can only access the clipboard from an STAThread.

The quickest way to solve this is to put [STAThread] on top of your Main() method, but if for whatever reason you cannot do that you can use a separate class that creates an STAThread set/get the string value for to you.

public static class Clipboard
{
    public static void SetText(string p_Text)
    {
        Thread STAThread = new Thread(
            delegate ()
            {
                // Use a fully qualified name for Clipboard otherwise it
                // will end up calling itself.
                System.Windows.Forms.Clipboard.SetText(p_Text);
            });
        STAThread.SetApartmentState(ApartmentState.STA);
        STAThread.Start();
        STAThread.Join();
    }
    public static string GetText()
    {
        string ReturnValue = string.Empty;
        Thread STAThread = new Thread(
            delegate ()
            {
                // Use a fully qualified name for Clipboard otherwise it
                // will end up calling itself.
                ReturnValue = System.Windows.Forms.Clipboard.GetText();
            });
        STAThread.SetApartmentState(ApartmentState.STA);
        STAThread.Start();
        STAThread.Join();

        return ReturnValue;
    }
}