我正在尝试从从列表派生的 MVC Controller 返回一个 csv 文件。我根据结合我从文档和 SO 问题中读到的内容为 Controller 提出了以下代码。我一定错过了一些东西,因为我收到了“无法访问关闭的流”的黄色死亡屏幕......
public class ConsumersFileController : Controller
{
private readonly TDCContext _db = new TDCContext();
public ActionResult Index()
{
IEnumerable<Consumer> list = _db.Consumers.ToList();
//put List in memory stream object
MemoryStream memoryStream = new MemoryStream();
using (memoryStream)
{
//return memory stream as file stream result:
using (BinaryWriter binaryWriter = new BinaryWriter(memoryStream, System.Text.Encoding.UTF8, true))
{
foreach (var item in list)
{
var itemBytes = item.Serialize();
binaryWriter.Write(itemBytes.Length);
binaryWriter.Write(itemBytes);
}
FileStreamResult fileStream =
new FileStreamResult(memoryStream, "application/txt") {FileDownloadName = "zips.csv"};
return fileStream;
}
}
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
_db.Dispose();
}
base.Dispose(disposing);
}
}
这是堆栈跟踪:
[ObjectDisposedException: Cannot access a closed Stream.]
System.IO.__Error.StreamIsClosed() +59
System.IO.MemoryStream.Read(Byte[] buffer, Int32 offset, Int32 count) +14731549
System.Web.Mvc.FileStreamResult.WriteFile(HttpResponseBase response) +93
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +88
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +831
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +81
System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +185
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +38
System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +29
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +67
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +52
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +36
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +38
System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +43
System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +67
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +38
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +607
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +134
如果我在
using
中返回结果,流如何关闭?流块?
最佳答案
你应该删除:
using (memoryStream)
FileStreamResult
将 dispose memoryStream
for you .您的代码不起作用的原因是从
memoryStream
读取的实际工作不在您的代码中 - 它在调用 fileStream.WriteFile
的 MVC 代码中.但是该代码在调用堆栈更高的某个地方执行。到时候WriteFile
被调用(需要 memoryStream
)你已经处理了它。
关于c# - 为什么 ASP.NET MVC Controller FileStreamResult 在关闭的流上出错?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45776611/