网络打印（TCP 直接发送到网络打印机）

【核心代码】

using System;
using System.IO;
using System.Net.Sockets;
using System.Threading.Tasks;

class Program
{
    static async Task Main()
    {
        Console.Write("请输入打印机 IP: ");
        string printerIp = Console.ReadLine()?.Trim();

        Console.Write("请输入本地文件路径: ");
        string filePath = Console.ReadLine()?.Trim();

        if (string.IsNullOrWhiteSpace(printerIp))
        {
            Console.WriteLine("打印机 IP 不能为空！");
            return;
        }

        if (string.IsNullOrWhiteSpace(filePath) || !File.Exists(filePath))
        {
            Console.WriteLine("文件不存在: "   filePath);
            return;
        }

        try
        {
            Console.WriteLine($"开始发送文件到打印机 {printerIp}:9100 ...");

            using (TcpClient client = new TcpClient())
            {
                await client.ConnectAsync(printerIp, 9100);

                using (NetworkStream stream = client.GetStream())
                using (FileStream fs = File.OpenRead(filePath))
                {
                    byte[] buffer = new byte[8192];
                    int bytesRead;

                    while ((bytesRead = await fs.ReadAsync(buffer, 0, buffer.Length)) > 0)
                    {
                        await stream.WriteAsync(buffer, 0, bytesRead);
                    }

                    await stream.FlushAsync();
                }
            }

            Console.WriteLine("打印任务发送完成！");
        }
        catch (Exception ex)
        {
            Console.WriteLine("打印失败："   ex.Message);
        }

        Console.WriteLine("按任意键退出...");
        Console.ReadKey();
    }
}