c# 打印电子发票

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Drawing.Printing;
using Spire.Pdf;

namespace InvoicePrint
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnUpload_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();

            //设置对话框标题
            openFileDialog.Title = "选择要打印的发票";
            //设置文件类型
            openFileDialog.Filter = "PDF文件|*.pdf|PDF文件|*.PDF";
            //默认加载目录
            openFileDialog.InitialDirectory = @"C:\";
            //记忆之前打开的对话框
            openFileDialog.RestoreDirectory = true;
            //多选
            openFileDialog.Multiselect = true;

            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {

                for (int i = 0; i < openFileDialog.SafeFileNames.Length; i++)
                {
                    //openFileDialog.SafeFileNames[i] 文件名扩展名
                    //openFileDialog.FileNames[i] 全路径及文件名
                    //lbFileList.Items.Add(openFileDialog.SafeFileNames[i]);
                    lbFileList.Items.Add(openFileDialog.FileNames[i]);

                }


            }



        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            Close();
        }

        private void btnPrint_Click(object sender, EventArgs e)
        {
            pdfPrint(lbFileList.Items[0].ToString());

        }

        void pdfPrint(string pdfFileName)
        {
            //加载需要打印的PDF文档
            PdfDocument doc=new Spire.Pdf.PdfDocument();
            doc.LoadFromFile(pdfFileName);

            //获取原文档第一页的纸张大小,这里的单位是Point

            SizeF size = doc.Pages[0].Size;

            //实例化PaperSize对象，设置其宽、高

            //需要特别注意的是这里涉及到单位的转换，PaperSize的宽高参数默认单位是百英寸 

            PaperSize paper = new PaperSize("Custom", (int)size.Width / 210 * 100, (int)size.Height / 72 * 100);

            paper.RawKind = (int)PaperKind.Custom;

            //设置打印的纸张大小为原来文档的大小

            doc.PrintSettings.PaperSize = paper;

            //需要选择FitSize打印模式

            doc.PrintSettings.SelectSinglePageLayout(PdfSinglePageScalingMode.FitSize, true);

            //打印

            doc.Print();
        }
    }

}