How to merge two .docx document with NPOI(C# .net)

I am trying to merge two .docx documents with NPOI(API for Microsoft documents written in C# .Net). But I could not find any tool to merge two .docx document together in NPOI. Is there any tool can perform like JAVA POI tool poi-tl and provide methods to merge two documents 's content together in sequence, keeping the style?

In JAVA POI, we can use poi-tl to merge two .docx documents. Here's the test code.

package com.mischen.mapreduce.wordcount; 
import com.deepoove.poi.xwpf.NiceXWPFDocument; 
import java.io.FileInputStream;
import java.io.FileOutputStream;
 
/**
 * @ClassName TestMergeWord
 * @Description DOTO
 * @Author mischen
 * @Date 2021/5/13 0013 23:16
 * @Version 1.0
 **/
public class TestMergeWord {
    public static void main(String[] args) throws Exception{
        NiceXWPFDocument main = new NiceXWPFDocument(new FileInputStream("C:\\Users\\Administrator\\Desktop\\PMP\\pmp记忆知识点.docx"));
 
        NiceXWPFDocument sub = new NiceXWPFDocument(new FileInputStream("C:\\Users\\Administrator\\Desktop\\PMP\\zookpeer.docx"));
 
        NiceXWPFDocument design = new NiceXWPFDocument(new FileInputStream("C:\\Users\\Administrator\\Desktop\\PMP\\设计模式.docx"));
 
        // 合并两个文档
        NiceXWPFDocument newDoc = main.merge(sub).merge(design);
        // 生成新文档
        FileOutputStream out = new FileOutputStream("C:\\Users\\Administrator\\Desktop\\PMP\\new_doc.docx");
        newDoc.write(out);
        newDoc.close();
        out.close();
        System.out.println("合并word成功！");
    }
}