void htmlRtb_DragDrop(object sender, System.Windows.DragEventArgs e)
{
Array arrayFileName = (Array)e.Data.GetData(DataFormats.FileDrop);
string strFileName = arrayFileName.GetValue(0).ToString();
string[] data = (string[])e.Data.GetData(DataFormats.FileDrop);
_thisForm.openfiles(data);
}