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

1.Stream转byte[]

 publicbyte[]StreamToByteArr(Streamstream)

 {

  byte[]bytes=newbyte[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

   returnbytes;

 }

2. byte[]转Image

publicstaticImageGetImageByBytes(byte[]bytes)

{

 Imagephoto=null;

 using(MemoryStreamms=newMemoryStream(bytes))

  {

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

    photo=Image.FromStream(ms,true);

   }

   returnphoto;

}

3.Image转Byte[]

publicbyte[]GetByteImage(Imageimg)

{

 byte[]bt=null;

 if(!img.Equals(null))

  {

   using(MemoryStreammostream=newMemoryStream())

    {

     Bitmapbmp=newBitmap(img);

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

     bt=newbyte[mostream.Length];

     mostream.Position= 0;

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

     }

  }

 returnbt;

}

4.Image图片缩放

publicImagepictureProcess(ImagesourceImage,inttargetWidth,inttargetHeight)

{

 intwidth;//图片最终的宽 

 intheight;//图片最终的高 

 try

  {

   System.Drawing.Imaging.ImageFormatformat=sourceImage.RawFormat;

   BitmaptargetPicture=newBitmap(targetWidth,targetHeight);

   Graphicsgraphics=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;

    }

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

    {

     height=targetHeight;

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

    }

    elseif(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();

    returntargetPicture;

  }

 catch(Exceptionex)

  {

  }

  returnnull;

}

5.byte[] 转bitmap

 publicstaticBitmapBytesToBitmap(byte[]Bytes)

{

   MemoryStreamstream=null;

  try

   {

     stream=newMemoryStream(Bytes);

     returnnewBitmap((Image)newBitmap(stream));

    }

   catch(ArgumentNullExceptionex)

    {

       throwex;

    }

    catch(ArgumentExceptionex)

     {

        throwex;

     }

     finally

     {

        stream.Close();

      }

}