方式一:

var rte = sender as RichTextEdit;control = rte.Controls[0] as RichEditControl;

方式二:

PropertyInfo myPropertyInfo1 = rte.GetType().GetProperty("InnerControl", BindingFlags.NonPublic | BindingFlags.Instance);control = myPropertyInfo1.GetValue(gridView1.ActiveEditor as RichTextEdit, null) as RichEditControl;