C#导出pdf的实现方法（浏览器不预览直接下载）

前言

这篇文章主要给大家介绍了关于c#导出pdf的实现方法，分享出来供大家参考学习，下面话不多说了，来一起看看详细的介绍吧

方法如下：

一.接口部分的代码

[httpget]
    public httpresponsemessage exportpdf(string id)
    {
      string pdfname = "";
　　　　　　　//id 查询条件，根据实际情况修改即可
　　　　　　　//pdfname 例如download.pdf
      byte[] pdfdata= _policygapmanagerservice.exportpdf(id, out pdfname);//获得pdf字节
      var result = new httpresponsemessage(httpstatuscode.ok)
      {
        content = new bytearraycontent(pdfdata)
      };
      result.content.headers.contentdisposition =
        new contentdispositionheadervalue("attachment")
        {
          filename = pdfname
        };
      result.content.headers.contenttype =new mediatypeheadervalue("application/pdf");
      return result;
    }

二.返回pdfbyte数组

1.下载http模式的pdf文件（以asp.net为例，将pdf存在项目的目录下，可以通过http直接打开项目下的pdf文件）

#region 调用本地文件使用返回pdfbyte数组

    /// <summary>
    /// 调用本地文件使用返回pdfbyte数组
    /// </summary>
    /// <param name="srcpdffile">‘d:\in2434341555551.pdf'</param>
    /// <returns></returns>

    public static byte[] getsignaturepdfbyte(string srcpdffile)
    {
      using (filestream fsread = new filestream(srcpdffile, filemode.open, fileaccess.read, fileshare.read))
      {
        int fslen = (int)fsread.length;
        byte[] hebyte = new byte[fslen];
        fsread.read(hebyte, 0, hebyte.length);
        return hebyte;
      }
    }

    #endregion 调用本地文件使用返回pdfbyte数组

    #region 从网站上下载pdf，转化为字节流


    /// <summary>
    /// 从网站上下载pdf，转化为字节流
    /// </summary>
    /// <param name="srcpdffile">文件地址：'https://******/group2/m00/00/04/wkj-mlpcoz2iubk5aacrpav6k98aaab6gaaaaaaaku9562.pdf'</param>

    /// <returns></returns>
    public static byte[] getbytebyremoteurl(string srcpdffile)
    {
      byte[] arrarybyte;
      httpwebrequest req = (httpwebrequest)httpwebrequest.create(srcpdffile);
      req.method = "get";
      using (webresponse wr = req.getresponse())
      {
        streamreader responsestream = new streamreader(wr.getresponsestream(), encoding.utf8);
        int length = (int)wr.contentlength;
        byte[] bs = new byte[length];

        httpwebresponse response = wr as httpwebresponse;
        stream stream = response.getresponsestream();

        //读取到内存
        memorystream stmmemory = new memorystream();
        byte[] buffer1 = new byte[length];
        int i;
        //将字节逐个放入到byte 中
        while ((i = stream.read(buffer1, 0, buffer1.length)) > 0)
        {
          stmmemory.write(buffer1, 0, i);
        }
        arrarybyte = stmmemory.toarray();
        stmmemory.close();
      }
      return arrarybyte;
    }

    #endregion 从网站上下载pdf，转化为字节流

    #region 从网站上下载文件，保存到其他路径

    /// <summary>
    /// 从网站上下载文件，保存到其他路径
    /// </summary>
    /// <param name="pdffile">文件地址</param>
    /// <param name="saveloadfile">保存文件路径：d:\12221.pdf</param>
    /// <returns></returns>
    public string saveremotefile( string saveloadfile , string pdffile)
    {
      //bool flag = false;
      var f = saveloadfile + guid.newguid().tostring("d") + ".pdf";
      uri downuri = new uri(pdffile);
      //建立一个ｗｅｂ请求，返回httpwebrequest对象
      httpwebrequest hwr = (httpwebrequest)webrequest.create(downuri);
      //流对象使用完后自动关闭
      using (stream stream = hwr.getresponse().getresponsestream())
      {
        //文件流，流信息读到文件流中，读完关闭
        using (filestream fs = file.create(f))
        {
          //建立字节组，并设置它的大小是多少字节
          byte[] bytes = new byte[102400];
          int n = 1;
          while (n > 0)
          {
            //一次从流中读多少字节，并把值赋给ｎ，当读完后，ｎ为０,并退出循环
            n = stream.read(bytes, 0, 10240);
            fs.write(bytes, 0, n);　//将指定字节的流信息写入文件流中
          }
        }
      }

      //return flag;
      //return _outpath + saveloadfile;
      return f;
    }

    #endregion 从网站上下载文件，保存到其他路径

2.ftp模式的pdf文件

/// <summary>
    /// 下载ftp文件。
    /// </summary>
    /// <param name="offsetpath">相对路径</param>
    /// <param name="filename">文件名称</param>
    /// <returns>下载结果，本地文件路径</returns>
    public string download(string offsetpath,string filename)
    {
      try
      {
        ftpwebrequest ftpweb = (ftpwebrequest)webrequest.create(_ftprootpath + offsetpath + filename);
        ftpweb.method = webrequestmethods.ftp.downloadfile;
        ftpweb.usebinary = true;
        var resp = ftpweb.getresponse();
        using (filestream fs = new filestream(_outpath + filename, filemode.create))
        {
          using (var s = resp.getresponsestream())
          {
            if (s == null) { return "文件不存在!"; }

            int readcout = 0;
            byte[] bytes = new byte[1024];
            readcout = s.read(bytes, 0, 1024);
            while (readcout > 0)
            {
              fs.write(bytes, 0, readcout);
              readcout = s.read(bytes, 0, 1024);
            }
          }
        }
        resp.close();
        return _outpath + filename;
      }
      catch (exception e)
      {
        return e.message;
      }
      
    }

    /// <summary>
    /// 判断文件是否存在
    /// </summary>
    /// <param name="offsetpath"></param>
    /// <param name="filename"></param>
    /// <returns></returns>
    public bool fileexists(string offsetpath, string filename)
    {
      try
      {
        ftpwebrequest ftpweb = (ftpwebrequest)webrequest.create(_ftprootpath + offsetpath + filename);
        ftpweb.method = webrequestmethods.ftp.downloadfile;
        ftpweb.usebinary = true;
        var resp = (ftpwebresponse)ftpweb.getresponse();
        resp.close();
        return true;
      }
      catch (exception)
      {
        return false;
      }
    }

    /// <summary>
    /// 获取目录下所有文件
    /// </summary>
    /// <returns></returns>
    public string[] files(string offsetpath)
    {
      try
      {
        ftpwebrequest ftpweb = (ftpwebrequest)webrequest.create(_ftprootpath + offsetpath);
        ftpweb.method = webrequestmethods.ftp.listdirectory;
        stream stream = ftpweb.getresponse().getresponsestream();
        if (stream == null)
        {
          return null;
        }
        list<string> filelist = new list<string>();
        using (streamreader sr = new streamreader(stream))
        {
          stringbuilder sb = new stringbuilder();
          do
          {
            sb.append(sr.readline());
            if (sb.length > 0)
            {
              filelist.add(sb.tostring());
              sb.clear();
            }
            else
            {
              break;
            }
          } while (true);
        }
        return filelist.toarray();
      }
      catch (exception)
      {
         return null;
      }
    }

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，谢谢大家对的支持。