如何使用PowerPoint API控制悬挂缩进

我正在用c#编程地创建一个PowerPoint 2007演示文稿，但是当我添加文本时，第二行缩进了。在UI中，我将通过Home->Paragraph->Indentation设置它，并将"Before Text"设置为"0"，Special设置为"(none)"。我如何通过编程来完成同样的事情?

        PowerPoint.Application app = new PowerPoint.Application();
        PowerPoint.Presentation p = app.Presentations.Add(Office.MsoTriState.msoTrue);
        app.Visible = Office.MsoTriState.msoTrue;
        PowerPoint.CustomLayout customLayout = p.SlideMaster.CustomLayouts[PowerPoint.PpSlideLayout.ppLayoutText];
        PowerPoint.Slide slide = p.Slides.AddSlide(p.Slides.Count + 1, customLayout);
        PowerPoint.Shape textShape = slide.Shapes[2];
        textShape.TextFrame.TextRange.ParagraphFormat.Bullet.Type = PowerPoint.PpBulletType.ppBulletNone;
        PowerPoint.TextRange range1 = textShape.TextFrame.TextRange.InsertAfter(@"Just enough text so that wrapping occurs.");
        range1.Font.Size = 54;
        p.SaveAs(@"c:'temp'test1.pptx", PowerPoint.PpSaveAsFileType.ppSaveAsDefault, Office.MsoTriState.msoTrue);
        p.Close();
        app.Quit();

所以…如何去掉悬挂缩进?