How do I deserialize binary data into an object in

问题:

I have an application which stores some data in a SQL database in a binary field. These data are serialized from a .net object in traditional .NET application with binary serialization. I'm writing a .net core application that needs to interface with the above but reading the binary data and making sense of them.

Ideally I want to be able just to deserialize these data with .net Core as if I was running full .net framework. The data itself are not complex, they are just a Dictionary<string,string> produced by the old asp.net profile provider.

I need to both read and write the binary data from .net core code.

I understand that support for BinaryFormatter is coming to .net core. In the meanwhile, is there anything not very complicated I can do right now to serialize / deserialize data with .net core as full .net framework would?

回答1:

Looks like we have to write our own BinaryReader/BinaryWriter methods...

SCHEMA

CREATE TABLE dbo.BinaryTest (
    BinaryData varbinary(max) NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO

CODE

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.IO;

namespace StackOverflow.ConsoleTester
{
    public class Program
    {
        private const String SqlConnectionString = @"Server={Server};Database={Database};User={User};Password={Password};";

        public static void Main(String[] args)
        {
            using (var db = new SqlConnection(SqlConnectionString))
            {
                var sqlCommand = new SqlCommand("DELETE FROM dbo.BinaryTest;", db) { CommandType = CommandType.Text };

                db.Open();

                sqlCommand.ExecuteNonQuery();
            }

            using (var db = new SqlConnection(SqlConnectionString))
            {
                var serializedData = new Dictionary<String, String> {{"key1", "value1"}, {"key2", "value2"}};

                var binaryData = WriteBinaryData(serializedData);

                var sqlCommand = new SqlCommand("INSERT INTO dbo.BinaryTest (BinaryData) VALUES (@BinaryData);", db) { CommandType = CommandType.Text };

                var parameter = new SqlParameter("BinaryData", SqlDbType.VarBinary) {Value = binaryData};

                sqlCommand.Parameters.Add(parameter);

                db.Open();

                sqlCommand.ExecuteNonQuery();
            }

            Dictionary<String, String> deserializedData = null;

            using (var db = new SqlConnection(SqlConnectionString))
            {
                var sqlCommand = new SqlCommand("SELECT BinaryData FROM dbo.BinaryTest", db) { CommandType = CommandType.Text };

                db.Open();

                var reader = sqlCommand.ExecuteReader();

                while (reader.Read())
                {
                    deserializedData = ReadBinaryData(reader.GetSqlBinary(0));
                }
            }

            if (deserializedData != null)
            {
                foreach (var item in deserializedData)
                {
                    Console.WriteLine($"Key: {item.Key}; Value: {item.Value}");
                }
            }

            Console.ReadKey();
        }

        private static Byte[] WriteBinaryData(Dictionary<String, String> data)
        {
            var memoryStream = new MemoryStream();
            var binaryWriter = new BinaryWriter(memoryStream);

            foreach (var item in data)
            {
                binaryWriter.Write(item.Key);
                binaryWriter.Write(item.Value);
            }

            var binaryData = memoryStream.ToArray();

            return binaryData;
        }

        private static Dictionary<String, String> ReadBinaryData(SqlBinary data)
        {
            var model = new Dictionary<String, String>();

            var memoryStream = new MemoryStream(data.Value);
            var binaryReader = new BinaryReader(memoryStream);

            while (binaryReader.BaseStream.Position != binaryReader.BaseStream.Length)
            {
                model.Add(binaryReader.ReadString(), binaryReader.ReadString());
            }

            return model;
        }
    }
}