修改rdlc图例的位置
代码如下：
  XmlDocument xmlDoc = new XmlDocument();
  string path = this.reportViewer1.LocalReport.ReportPath;
  xmlDoc.Load(path);

  XmlNode legendPosition = xmlDoc.GetElementsByTagName("Position").Item(0);
  legendPosition.InnerText = "TopCenter";

  MemoryStream ms = new MemoryStream();
  xmlDoc.Save(ms);
  ms.Position = 0;

  ReportDataSourceCollection rs = this.reportViewer1.LocalReport.DataSources;
  this.reportViewer1.Reset();
  this.reportViewer1.LocalReport.LoadReportDefinition(ms);
  this.reportViewer1.LocalReport.DataSources.Add(rs[0]);
  this.reportViewer1.Refresh();

问题：reportViewer1没有任何内容。
朋友们帮忙看一下哪个地方出错了，谢谢