C#实现上传下载图片

本文实例为大家分享了c#实现上传下载图片的具体代码，供大家参考，具体内容如下

1.首先我们通过流来上传下载图片，所有操作只停留在流这一层

memorystream ms;
  //左侧按钮
  private void button1_click(object sender, eventargs e)
  {  
   ms = new memorystream();
   image bi =picturebox1.image;
   bi.save(ms, picturebox1.image.rawformat);//将图片存入流中 
  }
  //右侧按钮
  private void button2_click(object sender, eventargs e)
  {
   image img = image.fromstream(ms, true);
   picturebox2.image = img; 
   ms.close();  
  }

分别点击左侧和右侧按钮，则将左侧图片加载到右侧：（picturebox的sizemode属性可以设置图片的填充方式）

2.通过将图片转化为流然后转化为字节；将字节转化为流，然后加载图片

图片转化为字节的代码：

public static byte[] imgtobyte(image img, system.drawing.imaging.imageformat imgformat)
  {
   bitmap bmp = new bitmap(img);
   memorystream memstream = new memorystream();
   bmp.save(memstream, imgformat);
   memstream.seek(0, seekorigin.begin); //及时定位流的开始位置
   byte[] btimage = new byte[memstream.length];
   memstream.read(btimage, 0, btimage.length);
   memstream.close();
   return btimage;
 }

字节转化为图片的代码：

public static image bytetoimg(byte[] btimage)
  {
   memorystream memstream = new memorystream();
   //stream memstream = null;
   memstream.write(btimage, 0, btimage.length);
   memstream.position = 0;
   memstream.seek(0, seekorigin.begin);
   //bitmap bmp = new bitmap(memstream, true);
   image img;
   try
   {
    img = image.fromstream(memstream, true);
    memstream.close();
    //img = new bitmap(memstream);
   }
   catch (exception ex)
   {
    img = null;
    messagebox.show(ex + "");
   }
   finally
   {
    memstream.close();
   }
   return img;
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。