/// <summary>
        /// 根据当前选中文本的上标或下标状态设置或取消上下标,同时同步按钮状态
        /// </summary>
        /// <param name="value"></param>
        private void SetSuperscriptOrSubscript(BaselineAlignment value)
        {
            BaselineAlignment curValue = rtfManager.GetSelectionBaselineAlignment();

            if (curValue != value)
            {
                rtfManager.SetSelectionBaselineAlignment(value);
            }
            else
            {
                rtfManager.SetSelectionBaselineAlignment(BaselineAlignment.Baseline);
            }
        }
        /// <summary>
        /// 根据当前选中文本的上标或下标状态设置或取消上下标,同时同步按钮状态
        /// </summary>
        /// <param name="value"></param>
        private void SetSuperscriptOrSubscript(BaselineAlignment value, ToggleButton btn)
        {
            BaselineAlignment curValue = rtfManager.GetSelectionBaselineAlignment();

            if (curValue != value)
            {
                rtfManager.SetSelectionBaselineAlignment(value);
                btn.IsChecked = true;
            }
            else
            {
                rtfManager.SetSelectionBaselineAlignment(BaselineAlignment.Baseline);
                btn.IsChecked = false;
            }
        }