Question

当我尝试从请求中读取多部分内容时，我得到一个异常，说明内容可能已被其他组件读取。

 if (MultipartRequestHelper.IsMultipartContentType(Request.ContentType))
            {
                // Used to accumulate all the form url encoded key value pairs in the 
                // request.
                var formAccumulator = new KeyValueAccumulator();

                var boundary = Request.GetMultipartBoundary();
                var reader = new MultipartReader(boundary, HttpContext.Request.Body);
                var section = await reader.ReadNextSectionAsync();
                while (section != null)
                {
                    ContentDispositionHeaderValue contentDisposition;
                    var hasContentDispositionHeader =
                        ContentDispositionHeaderValue.TryParse(section.ContentDisposition, out contentDisposition);
                }
            }

Answer 1

事实证明，我必须使用下面的属性禁用表单值模型绑定。

[HttpPost]
    [Route("")]
    [DisableFormValueModelBinding]
    public async Task<IActionResult> Post()

属性实现在

之下

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class DisableFormValueModelBindingAttribute : Attribute, IResourceFilter
{
    public void OnResourceExecuting(ResourceExecutingContext context)
    {
        var factories = context.ValueProviderFactories;
        factories.RemoveType<FormValueProviderFactory>();
        factories.RemoveType<JQueryFormValueProviderFactory>();
    }

    public void OnResourceExecuted(ResourceExecutedContext context)
    {
    }
}

Answer 2

在 asp.net核心3 中，您必须将factories.RemoveType<FormFileValueProviderFactory>();添加到DisableFormValueModelBindingAttribute属性中。

代码

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class DisableFormValueModelBindingAttribute : Attribute, IResourceFilter
{
    public void OnResourceExecuting(ResourceExecutingContext context)
    {
        var factories = context.ValueProviderFactories;
        factories.RemoveType<FormValueProviderFactory>();
        factories.RemoveType<FormFileValueProviderFactory>();
        factories.RemoveType<JQueryFormValueProviderFactory>();
    }

    public void OnResourceExecuted(ResourceExecutedContext context)
    {
    }
}

Documentation

Answer 3

This为netcore 3.1为我工作

您需要添加

factories.RemoveType<FormFileValueProviderFactory>();

关于这种方法

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class DisableFormValueModelBindingAttribute : Attribute, IResourceFilter
{
    public void OnResourceExecuting(ResourceExecutingContext context)
    {
        var factories = context.ValueProviderFactories;
        factories.RemoveType<FormValueProviderFactory>();
        factories.RemoveType<FormFileValueProviderFactory>();
        factories.RemoveType<JQueryFormValueProviderFactory>();
    }

    public void OnResourceExecuted(ResourceExecutedContext context)
    {
    }
}

Answer 4

我使用了[DisableFormValueModelBinding]，但仍然出现错误，然后我还使用了：

if (Request.ContentLength == 0)
                return BadRequest();

Answer 5

public class OpenCSVReaderReadAllExample { public static void main(String[] args) throws IOException { CSVReader reader = new CSVReader(new FileReader("emps.csv"), ','); List<String[]> records = reader.readAll(); Iterator<String[]> iterator = records.iterator(); while (iterator.hasNext()) { String[] record = iterator.next(); System.out.print(record[0]); System.out.print(record[0]); } reader.close(); } }中存在与此有关的错误。我将此软件包更新为Microsoft.AspNetCore.App 2.1.4版本，并解决了。

Answer 6

就我而言，这是“邮递员”问题。我已将文件发送到REST端点。到了某个时候，我开始出现此错误，但是代码没有更改。

我再次在“邮递员”中重新选择了此文件，一切正常。

Answer 7

在我的特定情况下，我使用的是由MultipartReader解析的有效负载中不存在的多部分边界值：

// multipartBoundary is not in the contents of httpResponseContentStream.
var multipartBoundary = "batchresponse_63d0e4c7-4d49-4961-a294-3902d1730c44";
var multipartReader = new MultipartReader(multipartBoundary, httpResponseContentStream);
// Unexpected end-of-stream error used to occur here:
var multipartSection = await multipartReader.ReadNextSectionAsync(cancellationToken);

一旦对multipartBoundary进行了更新以反映要解析的内容中存在的实际边界值，该代码就会按预期工作。

Answer 8

以防万一其他人正在追寻有关此错误的鬼魂：使用 net5 web api 我有一个控制器

    [HttpPost]
    [Route("api/fileupload/{reportId}")]
    [ResponseCache(Location = ResponseCacheLocation.None, NoStore = true)]
    public async Task<IActionResult> FileUpload(int reportId)

这不是个好主意。它给出了上述错误，我记得必须通过文件属性传递其他数据。那为我解决了。只是为了完整性。这不正常

    [HttpPost]
    [Route("api/fileupload")]
    [ResponseCache(Location = ResponseCacheLocation.None, NoStore = true)]
    public async Task<IActionResult> FileUpload()

意外结束Stream，内容可能已被另一个组件读取。 Microsoft.AspNetCore.WebUtilities.MultipartReaderStream

8 个答案: