Thread调用SaveFileDialog

        public void ThreadSaveFileDialog(string sourceFileName)
        {
            Thread importThread = new Thread(new ParameterizedThreadStart(SaveDialog));
            importThread.SetApartmentState(ApartmentState.STA); //重点
            importThread.IsBackground = true;
            importThread.Start(sourceFileName);

        }

        public static MainForm ScratchForm;//这个是主窗口
        private void SaveDialog(object sourceFileName)
        {
            SaveDialogShow(sourceFileName as string);

        }

        delegate void SaveDialogShowCallBack(string sourceFileName);
        private void SaveDialogShow(string sourceFileName)
        {
　　　　　　  //判断主窗口是否跨线程调用
            if (ScratchForm.InvokeRequired)
            {
                SaveDialogShowCallBack stcb = new SaveDialogShowCallBack(SaveDialogShow);
                ScratchForm.Invoke(stcb, new object[] { sourceFileName });
            }
            else
            {
　　　　　　　　　 //将saveFileDialog附加上主From上，否则的话点击主窗口会把savefiledialog给遮挡住。重复点击保存会弹出多个savefiledialog
                result = ScratchForm.saveFileDialog.ShowDialog(ScratchForm);
                if (result == DialogResult.OK)
                {
                    string destFileName = ScratchForm.saveFileDialog.FileName;
                    Task.Run(() =>
                    {
                        File.Copy(sourceFileName, destFileName, true);
                    });
                }
            }
        }