使用Office Automation，将文本框形状导出为Rtf

我正在编写一个应用程序，用于打开powerpoint演示文稿，查找形状列表，并将文本框的内容转换为Rtf。我可以很容易地从文本框中获取文本。下面的代码非常有效

string strFilePath = @"i:\work\test1.pptx";

PowerPoint.Application PowerPoint_App = new PowerPoint.Application();
try
{
   PowerPoint_App.Visible = Office.MsoTriState.msoFalse;
}
catch { }
PowerPoint.Presentations multi_presentations = PowerPoint_App.Presentations;
PowerPoint.Presentation presentation = multi_presentations.Open(strFilePath, Office.MsoTriState.msoFalse, Office.MsoTriState.msoFalse, Office.MsoTriState.msoFalse);

for (int i = 0; i < presentation.Slides.Count; i++)
{
   foreach (PowerPoint.Shape shape in presentation.Slides[i + 1].Shapes)
   {
      switch (shape.Type)
      {
         case Office.MsoShapeType.msoTextBox:
            if (shape.TextFrame.TextRange.Text.Length > 1)
            {
               Console.WriteLine("(x=" + shape.Left.ToString() + ", y=" + shape.Top.ToString() + ", 
                     w=" + shape.Width.ToString() + ", h=" + shape.Height.ToString() + ")\n" + 
                     shape.TextFrame.TextRange.Text + "\n");
            }
            break;
      }
   }
}

PowerPoint_App.Quit();

但在此之后，字符串为空。我想要的是字符串中的Rtf数据

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如果您有澄清问题，请告诉我。

您需要在复制之前选择一些内容：

编辑：我想这是正确的链接：

shape.TextFrame.TextRange.Copy();
string strRtfData = Clipboard.GetText(TextDataFormat.Rtf);