如何将图像对象转换为流 [英] how to convert an image object to stream

问题描述

Hye Everyone，



我在Windows Mobile 7工作，

我需要转换从相机中提取的图像流capturetask，

到字符串中将其保存在我的数据库中....

Hye Everyone,

I m working in Windows Mobile 7,
and i need to convert the image stream otained from the camera capturetask,
into string to save it in my database....

void photoChooser_Completed(object sender, PhotoResult e)
        {
            if (e.TaskResult == TaskResult.OK && e.ChosenPhoto != null)
            {
                 //Convert e.ChosenPhoto to string
            }
        }

我该怎么做。



i试过 -

how can i do this.

i have tried -

private byte[] imageByte = new Byte[e.ChosenPhoto.Length];
string imgStream = e.ChosenPhoto.Read(imageByte, 0, imageByte.Length);

但没有结果。



如何将流转换为字符串并返回流。



提前感谢

but no result.

how can i convert stream to string and back to stream.

thanks in advance

推荐答案

不要将它转换为字符串 - 将其转换为字节数组。字符串有一个默认的转换，你不需要图像数据，字节不是。大多数数据库都有一个VarBinary和一个VerChar，用于保存这些数据。



然后将图像转换为字节：

Don''t convert it to a string - convert it to a byte array. Strings have a default conversion which you do not want for image data, bytes don''t. Most databases have a VarBinary as well as a VerChar which is designed to hold such data.

Then convert the image to bytes:

public static byte[] ImageToByte(Image img)
{
    ImageConverter converter = new ImageConverter();
    return (byte[])converter.ConvertTo(img, typeof(byte[]));
}

如果您的框架不包含ImageConverter类（我不知道它是否存在），您可以通过将图像写入流来转换它，然后使用Stream.ToArray方法，但效率相当低。





我试过这个，但它给了一个例外



ConvertTo没有在Base Type转换器中实现。





什么我应该这样做。

以及

如何将这个字节数组转换回图像。



这可能意味着它没有在您的框架中实现 - 并非所有内容都在移动框架中。你可以通过更混乱的流：

If your framework doesn''t the include ImageConverter class (and I don''t know if it does) you can convert it by writing the image to a stream, and then using the Stream.ToArray method but that is quite a bit less efficient.


"i tried this, but it is giving an exception

ConvertTo not implemented in base TypeConverter.


what should i do.
and also,
how can i convert this byte array back to image."

That probably means it isn''t implemented in your framework - not everything is in the mobile frameworks. You can go via the messier stream though:

public static byte[] ImageToByteStream(Image img)
{    byte[] data = new byte[0];
    using (MemoryStream ms = new MemoryStream())
    {
        img.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
        ms.Seek(0,0);
        data = ms.ToArray();
    }
    return data;
}

最好使用Bitmap.FromStream方法反转过程返回图像。

It is probably best if you reverse the process to go back to an image using the Bitmap.FromStream method.

大家好，



您可以将Image对象转换为流：

Hi everyone,

You can convert an Image object to a stream as:

private Stream ImageToStream(Image image1)
{
     WriteableBitmap wb = new WriteableBitmap(400,400);
     wb.Render(image1, new TranslateTransform {X=400, Y=400});
     wb.Invalidate();


     Stream myStream = new MemoryStream();
     wb.SaveJpeg(myStream, 400, 400, 0, 70);
     return myStream;
}

干杯

Cheers

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