WPF中如何获取选中行/单元格所在行的数据

DataRowView dr = dg.SelectedItem as DataRowView;
            if (dr != null)
            {
                txt_id.Text = dr["ID"].ToString();
                time.SelectedDate = DateTime.Parse(dr["测试日期"].ToString());
                txt_cdbh.Text = dr["测点编号"].ToString();
                txt_cgqbh.Text = dr["传感器编号"].ToString();
                txt_sj1.Text = dr["应力数据1"].ToString();
                txt_sj2.Text = dr["应力数据2"].ToString();
                txt_t.Text = dr["温度"].ToString();