MemoryStream引发类型为InvalidOperationException的异常

时间:2019-07-17 17:59:27

标签: c# asp.net-mvc memorystream imagesharp

希望您能提供帮助:)

在我的MVC.net core 2.2中,调试简单时:

MemoryStream ms = new MemoryStream();

初始化后,它立即给我一个提示:

ReadTimeout: 'ms.ReadTimeout' threw an exception of type 'System.InvalidOperationException'
WriteTimeout: 'ms.WriteTimeout' threw an exception of type 'System.InvalidOperationException'

现在解决方案不会崩溃或什么。但是,如果我在Visual Studio中检查“ ms”,那就是它的意思。

我想做的是通过SixLabors.ImageSharp做:

IFormFile file = viewModel.File.Image;

using (Image<Rgba32> image = Image.Load(file.OpenReadStream()))
using (var ms = new MemoryStream())
{
    image.Mutate(x => x.Resize(1000, 1000));
    SixLabors.ImageSharp.Formats.Jpeg.JpegEncoder jpegEncoder = 
        new SixLabors.ImageSharp.Formats.Jpeg.JpegEncoder();
    jpegEncoder.Quality = 80;

    image.Save(ms, jpegEncoder);

    StorageCredentials storageCredentials = new StorageCredentials("Name", "KeyValue");

    // Create cloudstorage account by passing the storagecredentials
    CloudStorageAccount storageAccount = new CloudStorageAccount(storageCredentials, true);

    // Create the blob client.
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

    // Get reference to the blob container by passing the name by reading the value from the configuration (appsettings.json)
    CloudBlobContainer container = blobClient.GetContainerReference("storagefolder");

    // Get the reference to the block blob from the container
    CloudBlockBlob blockBlob = container.GetBlockBlobReference("image.jpg");

    await blockBlob.UploadFromStreamAsync(ms);
}

但是保存的流为空(调试时在“容量”,“长度”和“位置”中有值。但是将其上载到Azure Blob存储后,大小为0)。

亲切的问候 安达·亨德里克森

1 个答案:

答案 0 :(得分:1)

对内存流的写操作不是原子的,它们被缓冲以提高效率。您需要先刷新流。

第二个问题是,您要从流的末尾开始将内存流复制到输出流中。因此,将内存流重新定位到开头。

因此,在将流写入输出之前:

ms.Flush();
ms.Position = 0; // or ms.Seek(0, SeekOrigin.Begin);

然后拨打电话

await blockBlob.UploadFromStreamAsync(ms);