Question

我正在尝试从MVC控制器下载大文件 OutOfMemoryException 。我想减少对服务器内存的需求，那么如何在不先缓冲其全部内容的情况下下载文件呢？

我的代码是：

var cd = new System.Net.Mime.ContentDisposition
{
    FileName = filename,
    Inline = false
};
Response.AppendHeader("Content-Disposition", cd.ToString());

var stream = new MemoryStream();
ExportService service = new ExportService(_mapper, Repository);
service.ExportVersion(view.ExportType, version, products, regions, 
                      indicators, periods, stream);
stream.Position = 0;
return File(stream, "text/plain");

我希望在创建内容时将内容流式传输到浏览器。为了尝试实现这一点，我将Response.OutputStream传递给服务并写信给MemoryStream而不是OutOfMemoryException。但是，这会创建相同的Response.BufferOutput = false，因为默认情况下，ASP.NET会在将所有内容发送到浏览器之前对其进行缓冲。即使我设置EmptyResult（并返回OutOfMemoryException），我仍然会得到Response.BufferOutput = false; ExportService service = new ExportService(_mapper, Repository); service.ExportVersion(view.ExportType, version, products, regions, indicators, periods, Response.OutputStream); return new EmptyResult();。

[OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.]
    System.Collections.Generic.List`1.set_Capacity(Int32 value) +62
    System.Collections.Generic.List`1.EnsureCapacity(Int32 min) +43
    System.Collections.Generic.List`1.Add(T item) +51
    MyApp.Mapping.DocumentVersionEntityConverter.LoadMultiVariableData(DocumentVersion version, MultiVariableQuestionView view) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:207
    MyApp.Mapping.DocumentVersionEntityConverter.SetResponses(DocumentVersion version, List`1 questions, DataFilters filters) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:112
    MyApp.Mapping.DocumentVersionEntityConverter.ScanSection(DocumentVersion version, SectionView section, DataFilters filters) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:79
    MyApp.Mapping.DocumentVersionEntityConverter.Convert(ResolutionContext context) in c:\svn\Client Applications\MyApp\Web\Config\Mapping\DocumentVersionEntityConverter.cs:63   
    AutoMapper.DeferredInstantiatedConverter`2.Convert(ResolutionContext context) +57   
    AutoMapper.<>c__DisplayClass15.<ConvertUsing>b__14(ResolutionContext context) +10   
    AutoMapper.Mappers.CustomMapperStrategy.Map(ResolutionContext context, IMappingEngineRunner mapper) +13   
    AutoMapper.Mappers.TypeMapMapper.Map(ResolutionContext context, IMappingEngineRunner mapper) +130     
    AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) +355

更新

我确信此问题是由于达到了可用内存的限制，因为代码在一台计算机上运行，而在另一台计算机上运行。此外，在具有更多受限内存的机器上，strack跟踪显示错误发生在代码中的可变位置，具体取决于下载的内容。下面是一个示例堆栈跟踪，它显示了在为List对象分配内存时发生的异常：

app/etc/modules

下载没有缓冲的大文件

0 个答案: