在Office.Interop.Word C#中以文本形式插入水印

using Microsoft.Office.Interop.Word;

// 创建Word应用程序对象
Application wordApp = new Application();

// 打开指定的Word文档
Document doc = wordApp.Documents.Open("路径\\文件名.docx");

// 创建水印对象
Shape watermarkShape = doc.Shapes.AddTextEffect(MsoPresetTextEffect.msoTextEffect1, "水印文本", "Arial", 72, MsoTriState.msoFalse, MsoTriState.msoFalse, 0, 0);

// 设置水印文本的颜色
watermarkShape.Fill.ForeColor.RGB = System.Drawing.Color.Gray.ToArgb();

// 设置水印文本的透明度
watermarkShape.Fill.Transparency = 0.5f;

// 设置水印文本的旋转角度
watermarkShape.Rotation = -45;

// 设置水印文本的位置
watermarkShape.Left = (float)wdShapeCenter;
watermarkShape.Top = (float)wdShapeCenter;

// 将水印对象添加到Word文档中
doc.Sections[1].Headers[WdHeaderFooterIndex.wdHeaderFooterPrimary].Range.Select();
Selection selection = wordApp.Selection;
watermarkShape.Select();
selection.ShapeRange.Group.Select();
selection.ShapeRange.LockAspectRatio = MsoTriState.msoFalse;
selection.ShapeRange.Height = wordApp.InchesToPoints(5);
selection.ShapeRange.Width = wordApp.InchesToPoints(8);
selection.ShapeRange.WrapFormat.AllowOverlap = -1;
selection.ShapeRange.WrapFormat.Side = WdWrapSideType.wdWrapBoth;
selection.ShapeRange.WrapFormat.Type = WdWrapType.wdWrapNone;
selection.ShapeRange.RelativeHorizontalPosition = WdRelativeHorizontalPosition.wdRelativeHorizontalPositionMargin;
selection.ShapeRange.RelativeVerticalPosition = WdRelativeVerticalPosition.wdRelativeVerticalPositionMargin;
selection.ShapeRange.Left = (float)wdShapeCenter;
selection.ShapeRange.Top = (float)wdShapeCenter;
selection.ShapeRange.RelativeHorizontalSize = WdRelativeHorizontalSize.wdRelativeHorizontalSizeMargin;
selection.ShapeRange.RelativeVerticalSize = WdRelativeVerticalSize.wdRelativeVerticalSizeMargin;

// 保存Word文档
doc.Save();

// 关闭Word文档和应用程序对象
doc.Close();
wordApp.Quit();