官方论坛

官方论坛的解决方案：

   static void Main(string[] args)
    {
        Document doc = new Document();
        doc.LoadFromFile("目录.docx");
        foreach (Section section in doc.Sections)
        {
            //遍历body下面所有对象
            foreach (DocumentObject obj in section.Body.ChildObjects)
            {
                if (obj is Paragraph)
                {
                    Paragraph para = obj as Paragraph;
                    //通过样式名来确定是否是目录文本
                    switch(para.StyleName){
                        //一级标题
                        case "TOC1":
                            ChangeFont(para, "黑体", 14);
                            break;
                        //二级标题
                        case "TOC2":
                            ChangeFont(para, "黑体", 12);
                            break;
                        //三级标题
                        case "TOC3":
                            ChangeFont(para, "黑体", 10);
                            break;
                        //其余级别类推
                    }
                }
            }
        }
        doc.SaveToFile("结果.docx", FileFormat.Docx);
    }

    public static void ChangeFont(Paragraph para, string fontName, int fontSize)
    {
        foreach (DocumentObject obj in para.ChildObjects)
        {
            //如果对象类型为TextRange
            if (obj.DocumentObjectType == DocumentObjectType.TextRange)
            {
                TextRange tr = (TextRange)obj;
                //更改字体和文字大小
                tr.CharacterFormat.FontName = fontName;
                tr.CharacterFormat.FontSize = fontSize;
            }
        }
    }

但是我发现这样不行，稍微改了一下：

   static void Main(string[] args)
    {
        Document doc = new Document();
        doc.LoadFromFile("目录.docx");
        foreach (Section section in doc.Sections)
        {
            //遍历body下面所有对象
            foreach (DocumentObject obj in section.Body.ChildObjects)
            {
                if (obj is Paragraph)
                {
                    Paragraph para = obj as Paragraph;
					for (DocumentObject tr : (Iterable<? extends DocumentObject>) para.getChildObjects()) {
                        if (tr.getDocumentObjectType() == DocumentObjectType.TOC || 		tr.getDocumentObjectType() == DocumentObjectType.Field) {
                            ChangeFont(para,"黑体",14);
                        }
                }
            }
        }
        doc.SaveToFile("结果.docx", FileFormat.Docx);
    }

    public static void ChangeFont(Paragraph para, string fontName, int fontSize)
    {
        foreach (DocumentObject obj in para.ChildObjects)
        {
            //如果对象类型为TextRange
            if (obj.DocumentObjectType == DocumentObjectType.TextRange)
            {
                TextRange tr = (TextRange)obj;
                //更改字体和文字大小
                tr.CharacterFormat.FontName = fontName;
                tr.CharacterFormat.FontSize = fontSize;
            }
        }
    }