VSTO自动添加的水印变得失真了，C＃VSTO

如何解决VSTO自动添加的水印变得失真了，C＃VSTO

我都是VSTO和c＃的新手，我正在尝试通过VSTO自动化在Word文档中添加水印。我可以添加水印，但是在添加一些文本后，水印变得失真了（高度在减小）

让我知道您是否需要任何信息

预先感谢下面是我的代码

foreach (Word.Section section in doc.Sections)
            {
                Object oMissing = System.Reflection.Missing.Value;
                Word.Shape shape = 
                    section.Headers[Word.WdheaderfooterIndex.wdheaderfooterPrimary].Shapes
                    .AddTextEffect(MsoPresetTextEffect.msoTextEffect2,"confidential","Calibri",5,MsoTriState.msoTrue,MsoTriState.msoFalse,ref oMissing);
                //shape.Select(ref oMissing);
                shape.Name = "WaterMark";
                shape.Line.Visible = MsoTriState.msoFalse;
                shape.TextEffect.normalizedHeight = MsoTriState.msoFalse;
                shape.TextEffect.FontItalic = MsoTriState.msoFalse;
                shape.TextEffect.FontBold = MsoTriState.msoFalse;
                shape.Fill.Visible = MsoTriState.msoTrue;
                shape.Fill.solid();
                shape.Fill.ForeColor.RGB = 12632256;
                shape.Fill.Transparency = (float)0.5;
                shape.Rotation = 315;
                shape.LockAspectRatio = MsoTriState.msoTrue;
                shape.Left = (float)Word.WdShapePosition.wdShapeCenter;
                shape.LeftRelative = (float)-999999;
                shape.Top = (float)Word.WdShapePosition.wdShapeCenter;
                shape.TopRelative = (float)-999999;
                shape.Height = Globals.ThisAddIn.Application.CentimetersToPoints((float)3.65);
                shape.Width = Globals.ThisAddIn.Application.CentimetersToPoints((float)12.62);
                shape.Wrapformat.Type = Word.WdWrapType.wdWrapBehind;
                shape.Wrapformat.AllowOverlap = -1;
                shape.Wrapformat.distanceBottom = 0;
                shape.Wrapformat.distanceLeft = 9;
                shape.Wrapformat.distanceRight = 9;
                shape.Wrapformat.distancetop = 0;
                shape.Wrapformat.Side = WdWrapSideType.wdWrapBoth;
                shape.RelativeVerticalPosition = Word.WdRelativeVerticalPosition.wdRelativeVerticalPositionMargin;
                shape.RelativeHorizontalPosition = Word.WdRelativeHorizontalPosition.wdRelativeHorizontalPositionMargin;
                shape.WidthRelative = (float)-999999;
                doc.ActiveWindow.ActivePane.View.SeekView = Word.WdSeekView.wdSeekMainDocument;
                

            }