c# - 图像变量到 byte[] 数组

Question

我遇到了一个我认为很容易解决的问题，只是我做错了一些事情，所以: 我有一个 Android 平板电脑，用户可以在其中绘制签名，我通过 adb 获取图像(.JPEG)。

    ProcessStartInfo adb_copy = new ProcessStartInfo("C:/SCR/adb/adb.exe");
    adb_copy.Arguments = "pull \"mnt/sdcard/sign.jpg\" \"C:\\SCR\\temp\\sign.jpg\"";
    adb_copy.WindowStyle = ProcessWindowStyle.Hidden;
    Process.Start(adb_copy);

我有两个Image变量:

Image WORKER_sign;
Image EMPLOYER_sign;

我将图像加载到这些中，也加载到图片框中:

    using (FileStream stream = new FileStream("C:/SCR/temp/sign.jpg", FileMode.Open, FileAccess.Read))
    {
        WORKER_sign = Image.FromStream(stream);
        stream.Close();
    }
    pictureBox3.Image = WORKER_sign;
    pictureBox3.SizeMode = PictureBoxSizeMode.Zoom;

图片框完美地显示了图像，但是我无法写入字节数组。我尝试了以下代码:

public static byte[] ImageToByte(Image img)
{
    if (img == null) return null;
    byte[] result;
    using (MemoryStream stream = new MemoryStream())
    {
        img.Save(stream, img.RawFormat);
        result = stream.GetBuffer();
    }
    return result;
}
byte[] temparray = ImageToByte(WORKER_SIGN);

但是最后一行向我抛出了一个通用 GDI+ 异常，在此之前 IntelliTrace 也显示了一些 System.ObjectDisposeException(“已关闭文件”)。

我的代码有什么问题吗？ 感谢您的所有帮助! :)

关闭:抱歉我的英语不好...

编辑:错误:

Exception:Thrown: "Cannot access a closed Stream." (System.ObjectDisposedException) A System.ObjectDisposedException was thrown: "Cannot access a closed Stream." Time: 2014.08.11. 14:37:49 Thread:Main Thread[7276]

Exception:Thrown: "Generic error in: GDI+." (System.Runtime.InteropServices.ExternalException) A System.Runtime.InteropServices.ExternalException was thrown: "Generic error in: GDI+." Time: 2014.08.11. 14:37:49 Thread:Main Thread[7276]

Answer 1

将代码更改为:

public static byte[] ImageToByte(Image img)
{
    if (img == null) return null;
    byte[] result;
    using (MemoryStream stream = new MemoryStream())
    {
        img.Save(stream, img.RawFormat);
        result = stream.ToArray();
    }
    return result;
}