在文件中保存和加载 MemoryStream

Question

I am serializing an structure into a MemoryStream and I want to save and load the serialized structure.

So, How to Save a MemoryStream into a file and also load it back from file?

Answer 1

You may use MemoryStream.WriteTo or Stream.CopyTo (supported in framework version 4.5.2, 4.5.1, 4.5, 4) methods to write content of memory stream to another stream.

memoryStream.WriteTo(fileStream);

Update:

fileStream.CopyTo(memoryStream);
memoryStream.CopyTo(fileStream);

Answer 2

Assuming that MemoryStream name is ms .

This code writes down MemoryStream to a file:

using (FileStream file = new FileStream("file.bin", FileMode.Create, System.IO.FileAccess.Write)) {
   byte[] bytes = new byte[ms.Length];
   ms.Read(bytes, 0, (int)ms.Length);
   file.Write(bytes, 0, bytes.Length);
   ms.Close();
}

and this reads a file to a MemoryStream :

using (MemoryStream ms = new MemoryStream())
using (FileStream file = new FileStream("file.bin", FileMode.Open, FileAccess.Read)) {
   byte[] bytes = new byte[file.Length];
   file.Read(bytes, 0, (int)file.Length);
   ms.Write(bytes, 0, (int)file.Length);
}

In .Net Framework 4+, You can simply copy FileStream to MemoryStream and reverse as simple as this:

MemoryStream ms = new MemoryStream();
using (FileStream file = new FileStream("file.bin", FileMode.Open, FileAccess.Read))
    file.CopyTo(ms);

And the Reverse (MemoryStream to FileStream):

using (FileStream file = new FileStream("file.bin", FileMode.Create, System.IO.FileAccess.Write))
    ms.CopyTo(file);

Answer 3

The stream should really by disposed of even if there's an exception (quite likely on file I/O) - using clauses are my favourite approach for this, so for writing your MemoryStream, you can use:

using (FileStream file = new FileStream("file.bin", FileMode.Create, FileAccess.Write)) {
    memoryStream.WriteTo(file);
}

And for reading it back:

using (FileStream file = new FileStream("file.bin", FileMode.Open, FileAccess.Read)) {
    byte[] bytes = new byte[file.Length];
    file.Read(bytes, 0, (int)file.Length);
    ms.Write(bytes, 0, (int)file.Length);
}

If the files are large, then it's worth noting that the reading operation will use twice as much memory as the total file size . One solution to that is to create the MemoryStream from the byte array - the following code assumes you won't then write to that stream.

MemoryStream ms = new MemoryStream(bytes, writable: false);

My research (below) shows that the internal buffer is the same byte array as you pass it, so it should save memory.

byte[] testData = new byte[] { 104, 105, 121, 97 };
var ms = new MemoryStream(testData, 0, 4, false, true);
Assert.AreSame(testData, ms.GetBuffer());

Answer 4

For anyone looking for the short versions:

var memoryStream = new MemoryStream(File.ReadAllBytes("1.dat"));

File.WriteAllBytes("1.dat", memoryStream.ToArray()); 

Answer 5

The combined answer for writing to a file can be;

MemoryStream ms = new MemoryStream();    
FileStream file = new FileStream("file.bin", FileMode.Create, FileAccess.Write);
ms.WriteTo(file);
file.Close();
ms.Close();

Answer 6

Save into a file

Car car = new Car();
car.Name = "Some fancy car";
MemoryStream stream = Serializer.SerializeToStream(car);
System.IO.File.WriteAllBytes(fileName, stream.ToArray());

Load from a file

using (var stream = new MemoryStream(System.IO.File.ReadAllBytes(fileName)))
{
    Car car = (Car)Serializer.DeserializeFromStream(stream);
}

where

using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

namespace Serialization
{
    public class Serializer
    {
        public static MemoryStream SerializeToStream(object o)
        {
            MemoryStream stream = new MemoryStream();
            IFormatter formatter = new BinaryFormatter();
            formatter.Serialize(stream, o);
            return stream;
        }

        public static object DeserializeFromStream(MemoryStream stream)
        {
            IFormatter formatter = new BinaryFormatter();
            stream.Seek(0, SeekOrigin.Begin);
            object o = formatter.Deserialize(stream);
            return o;
        }
    }
}

Originally the implementation of this class has been posted here

and

[Serializable]
public class Car
{
    public string Name;
}

Answer 7

For loading a file, I like this a lot better

MemoryStream ms = new MemoryStream();
using (FileStream fs = File.OpenRead(file))
{
    fs.CopyTo(ms);
}

Answer 8

I use a Panel Control to add a image or even stream video, but you can save the image on SQL Server as Image or MySQL as largeblob . This code works for me a lot. Check it out.

Here you save the image

MemoryStream ms = new MemoryStream();
Bitmap bmp = new Bitmap(panel1.Width, panel1.Height);
panel1.DrawToBitmap(bmp, panel1.Bounds);
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); // here you can change the Image format
byte[] Pic_arr = new byte[ms.Length];
ms.Position = 0;
ms.Read(Pic_arr, 0, Pic_arr.Length);
ms.Close();

And here you can load, but I used a PictureBox Control.

MemoryStream ms = new MemoryStream(picarr);
ms.Seek(0, SeekOrigin.Begin);
fotos.pictureBox1.Image = System.Drawing.Image.FromStream(ms);

Hope helps.

Answer 9

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Text;

namespace ImageWriterUtil
{
    public class ImageWaterMarkBuilder
    {
        //private ImageWaterMarkBuilder()
        //{
        //}
        Stream imageStream;
        string watermarkText = "©8Bytes.Technology";
        Font font = new System.Drawing.Font("Brush Script MT", 30, FontStyle.Bold, GraphicsUnit.Pixel);
        Brush brush = new SolidBrush(Color.Black);
        Point position;
        public ImageWaterMarkBuilder AddStream(Stream imageStream)
        {
            this.imageStream = imageStream;
            return this;
        }
        public ImageWaterMarkBuilder AddWaterMark(string watermarkText)
        {
            this.watermarkText = watermarkText;
            return this;
        }
        public ImageWaterMarkBuilder AddFont(Font font)
        {
            this.font = font;
            return this;
        }

        public ImageWaterMarkBuilder AddFontColour(Color color)
        {
            this.brush = new SolidBrush(color);
            return this;
        }
        public ImageWaterMarkBuilder AddPosition(Point position)
        {
            this.position = position;
            return this;
        }

        public void CompileAndSave(string filePath)
        {

            //Read the File into a Bitmap.
            using (Bitmap bmp = new Bitmap(this.imageStream, false))
            {
                using (Graphics grp = Graphics.FromImage(bmp))
                {


                    //Determine the size of the Watermark text.
                    SizeF textSize = new SizeF();
                    textSize = grp.MeasureString(watermarkText, font);

                    //Position the text and draw it on the image.
                    if (position == null)
                        position = new Point((bmp.Width - ((int)textSize.Width + 10)), (bmp.Height - ((int)textSize.Height + 10)));
                    grp.DrawString(watermarkText, font, brush, position);

                    using (MemoryStream memoryStream = new MemoryStream())
                    {
                        //Save the Watermarked image to the MemoryStream.
                        bmp.Save(memoryStream, ImageFormat.Png);
                        memoryStream.Position = 0;
                       // string fileName = Path.GetFileNameWithoutExtension(filePath);
                        // outPuthFilePath = Path.Combine(Path.GetDirectoryName(filePath), fileName + "_outputh.png");
                        using (FileStream file = new FileStream(filePath, FileMode.Create, System.IO.FileAccess.Write))
                        {
                            byte[] bytes = new byte[memoryStream.Length];
                            memoryStream.Read(bytes, 0, (int)memoryStream.Length);
                            file.Write(bytes, 0, bytes.Length);
                            memoryStream.Close();
                        }
                    }
                }
            }

        }
    }
}

Usage :-

ImageWaterMarkBuilder.AddStream(stream).AddWaterMark("").CompileAndSave(filePath);