在 PostgreSQL中解决图片二进制数据由于bytea_output参数问题导致显示不正常的问题

class Program
{
    static void Main()
    {
        string connString = "Host=myServerAddress;Port=myPort;Username=myUsername;Password=myPassword;Database=myDatabase";
        using (var conn = new NpgsqlConnection(connString))
        {
            conn.Open();
            // 执行 SQL 查询以获取图像数据
            string sql = "SELECT image_column FROM your_table WHERE id = @id";
            int id = 1; // 替换为你要查询的图像的 ID
            using (var cmd = new NpgsqlCommand(sql, conn))
            {
                cmd.Parameters.AddWithValue("@id", id);
                // 读取图像数据
                using (var reader = cmd.ExecuteReader(CommandBehavior.SequentialAccess))
                {
                    if (reader.Read())
                    {
                        // 获取十六进制字符串
                        string hexString = reader.GetString(0);
                        // 将十六进制字符串转换为字节数组
                        byte[] imageData = StringToByteArray(hexString);
                        // 创建图像对象
                        using (MemoryStream ms = new MemoryStream(imageData))
                        {
                            Image image = Image.FromStream(ms);
                            // 显示图像
                            ShowImage(image);
                        }
                    }
                }
            }
        }
    }
    static void ShowImage(Image image)
    {
        // 创建一个新的窗体
        using (var form = new System.Windows.Forms.Form())
        {
            // 创建 PictureBox 控件
            var pictureBox = new System.Windows.Forms.PictureBox();
            pictureBox.Dock = System.Windows.Forms.DockStyle.Fill;
            pictureBox.Image = image;
            // 将 PictureBox 添加到窗体中
            form.Controls.Add(pictureBox);
            // 设置窗体大小并显示
            form.Size = new System.Drawing.Size(image.Width, image.Height);
            form.ShowDialog();
        }
    }
    static byte[] StringToByteArray(string hex)
    {
        int NumberChars = hex.Length / 2;
        byte[] bytes = new byte[NumberChars];
        using (var sr = new StringReader(hex))
        {
            for (int i = 0; i < NumberChars; i++)
                bytes[i] = Convert.ToByte(new string(new char[2] { (char)sr.Read(), (char)sr.Read() }), 16);
        }
        return bytes;
    }
}

using Npgsql;
using System;
using System.Data;
using System.Drawing;
using System.IO;
class Program
{
    static void Main()
    {
        string connString = "Host=myServerAddress;Port=myPort;Username=myUsername;Password=myPassword;Database=myDatabase";
        using (var conn = new NpgsqlConnection(connString))
        {
            conn.Open();
            // 执行 SQL 查询以获取图像数据
            string sql = "SELECT image_column FROM your_table WHERE id = @id";
            int id = 1; // 替换为你要查询的图像的 ID
            using (var cmd = new NpgsqlCommand(sql, conn))
            {
                cmd.Parameters.AddWithValue("@id", id);
                // 读取图像数据
                using (var reader = cmd.ExecuteReader(CommandBehavior.SequentialAccess))
                {
                    if (reader.Read())
                    {
                        // 获取图像数据字节数组
                        byte[] imageData = (byte[])reader["image_column"];
                        // 创建图像对象
                        using (MemoryStream ms = new MemoryStream(imageData))
                        {
                            Image image = Image.FromStream(ms);
                            // 显示图像
                            ShowImage(image);
                        }
                    }
                }
            }
        }
    }
    static void ShowImage(Image image)
    {
        // 创建一个新的窗体
        using (var form = new System.Windows.Forms.Form())
        {
            // 创建 PictureBox 控件
            var pictureBox = new System.Windows.Forms.PictureBox();
            pictureBox.Dock = System.Windows.Forms.DockStyle.Fill;
            pictureBox.Image = image;
            // 将 PictureBox 添加到窗体中
            form.Controls.Add(pictureBox);
            // 设置窗体大小并显示
            form.Size = new System.Drawing.Size(image.Width, image.Height);
            form.ShowDialog();
        }
    }
}