C# 转换函数 （Stream to Byte[],Byte to Image,Image to Byte[],Image缩放,Byte[] to Bitmap）

1.Stream转byte[]

  public byte[] StreamToByteArr(Stream stream)

 {

   byte[] bytes = new byte[stream.Length]; //创建byte数组

    stream.Read(bytes, 0, bytes.Length); //将Stream读入byte数组

   stream.Seek(0, SeekOrigin.Begin);// 将流指向起始位置

    return bytes;

 }

2. byte[]转Image

public static Image GetImageByBytes(byte[] bytes)

{

  Image photo = null;

  using (MemoryStream ms = new MemoryStream(bytes))

  {

      ms.Write(bytes, 0, bytes.Length);

     photo = Image.FromStream(ms, true);

   }

    return photo;

}

3.Image转Byte[]

public byte[] GetByteImage(Image img)

{

  byte[] bt = null;

  if (!img.Equals(null))

  {

    using (MemoryStream mostream = new MemoryStream())

    {

      Bitmap bmp = new Bitmap(img);

      bmp.Save(mostream, System.Drawing.Imaging.ImageFormat.Bmp);

      bt = new byte[mostream.Length];

      mostream.Position = 0;

      mostream.Read(bt, 0, Convert.ToInt32(bt.Length));

     }

  }

  return bt;

}

4.Image图片缩放

public Image pictureProcess(Image sourceImage, int targetWidth, int targetHeight)

{

  int width;//图片最终的宽 

  int height;//图片最终的高 

  try

  {

    System.Drawing.Imaging.ImageFormat format = sourceImage.RawFormat;

    Bitmap targetPicture = new Bitmap(targetWidth, targetHeight);

    Graphics graphics = Graphics.FromImage(targetPicture);

    graphics .Clear(Color.White);

    //计算缩放图片的大小 

    if (sourceImage.Width > targetWidth && sourceImage.Height <= targetHeight)

    {

      width = targetWidth;

      height = (width * sourceImage.Height) / sourceImage.Width;

    }

    else if (sourceImage.Width <= targetWidth && sourceImage.Height > targetHeight)

    {

      height = targetHeight;

       width = (height * sourceImage.Width) / sourceImage.Height;

    }

     else if (sourceImage.Width <= targetWidth && sourceImage.Height <= targetHeight)

    {

      width = sourceImage.Width;

      height = sourceImage.Height;

    }

    else

    {

      width = targetWidth;

      height = (width * sourceImage.Height) / sourceImage.Width;

      if (height > targetHeight)

      {

        height = targetHeight;

        width = (height * sourceImage.Width) / sourceImage.Height;

       }

    }

     graphics .DrawImage(sourceImage, (targetWidth - width) / 2, (targetHeight - height) / 2, width, height);

     sourceImage.Dispose();

     return targetPicture;

  }

  catch (Exception ex)

  {

  }

   return null;

}

5.byte[] 转bitmap

 public static Bitmap BytesToBitmap(byte[] Bytes)

{

    MemoryStream stream = null;

   try

   {

      stream = new MemoryStream(Bytes);

      return new Bitmap((Image)new Bitmap(stream));

    }

    catch (ArgumentNullException ex)

    {

        throw ex;

    }

     catch (ArgumentException ex)

     {

         throw ex;

     }

      finally

     {

         stream.Close();

      }

}