Image.Save(..) 抛出 GDI+ 异常，因为内存流已关闭 [英] Image.Save(..) throws a GDI+ exception because the memory stream is closed

问题描述

我有一些二进制数据要保存为图像.当我尝试保存图像时，如果用于创建图像的内存流在保存之前关闭，则会引发异常.我这样做的原因是因为我正在动态创建图像，因此..我需要使用内存流.

i've got some binary data which i want to save as an image. When i try to save the image, it throws an exception if the memory stream used to create the image, was closed before the save. The reason i do this is because i'm dynamically creating images and as such .. i need to use a memory stream.

这是代码:

[TestMethod]
public void TestMethod1()
{
    // Grab the binary data.
    byte[] data = File.ReadAllBytes("Chick.jpg");

    // Read in the data but do not close, before using the stream.
    Stream originalBinaryDataStream = new MemoryStream(data);
    Bitmap image = new Bitmap(originalBinaryDataStream);
    image.Save(@"c:	est.jpg");
    originalBinaryDataStream.Dispose();

    // Now lets use a nice dispose, etc...
    Bitmap2 image2;
    using (Stream originalBinaryDataStream2 = new MemoryStream(data))
    {
        image2 = new Bitmap(originalBinaryDataStream2);
    }

    image2.Save(@"C:	emppewpew.jpg"); // This throws the GDI+ exception.
}

有人对我如何在关闭流的情况下保存图像有任何建议吗?我不能依赖开发人员记住在保存图像后关闭流.事实上，开发人员不知道图像是使用内存流生成的(因为它发生在其他地方的其他代码中).

Does anyone have any suggestions to how i could save an image with the stream closed? I cannot rely on the developers to remember to close the stream after the image is saved. In fact, the developer would have NO IDEA that the image was generated using a memory stream (because it happens in some other code, elsewhere).

我真的很困惑:(

推荐答案

因为它是一个 MemoryStream，你真的需要关闭流 - 如果你不这样做，没有什么不好的事情发生，尽管无论如何处理任何一次性物品显然是一种很好的做法.(有关详情，请参阅这个问题.)

As it's a MemoryStream, you really don't need to close the stream - nothing bad will happen if you don't, although obviously it's good practice to dispose anything that's disposable anyway. (See this question for more on this.)

但是，您应该处理位图 - 这将为您关闭流.基本上，一旦您为 Bitmap 构造函数提供了一个流，它就拥有"了该流，您不应关闭它.正如该构造函数的文档所说:

However, you should be disposing the Bitmap - and that will close the stream for you. Basically once you give the Bitmap constructor a stream, it "owns" the stream and you shouldn't close it. As the docs for that constructor say:

您必须保持流打开位图的生命周期.

You must keep the stream open for the lifetime of the Bitmap.

我找不到任何承诺在您处理位图时关闭流的文档，但您应该能够很容易地验证这一点.

I can't find any docs promising to close the stream when you dispose the bitmap, but you should be able to verify that fairly easily.

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