尝试将 base64String 转换为 IFormFile 在 C# 中引发 SystemInvalidOperation 异常

Question

我正在尝试将 base64String 列表转换为 IFormFile 列表。当我尝试 MemoryStream stream = new MemoryStream(bytes) 时，我得到了 stream.ReadTimeout SystemInvalidOperation。那么为什么它不起作用？

这是我的代码：

private async Task<List<IFormFile>> Base64ToImage(List<EquipmentFile> equipmentFiles)
{
    List<IFormFile> formFiles = new List<IFormFile>();
    foreach (var eqp in equipmentFiles)
    {
      byte[] bytes = Convert.FromBase64String(eqp.File);
      MemoryStream stream = new MemoryStream(bytes);
      IFormFile file = new FormFile(stream, 0, bytes.Length, eqp.Name, eqp.Name);
      formFiles.Add(file);
    }
    return formFiles;
}

我的堆栈跟踪：

System.InvalidOperationException: Timeouts are not supported on this stream.
   at System.IO.Stream.get_ReadTimeout()
   at FieldService.CallCenter.Api.Controllers.EquipmentLibraryController.Base64ToImage(List`1 equipmentFiles) in C:\Users\CMTech-DEV\Documents\cmtech\fieldservice-api\src\CallCenter\FieldService.CallCenter.API\Controllers\EquipmentLibraryController.cs:line 331
   at System.IO.Stream.get_ReadTimeout()
   at FieldService.CallCenter.Api.Controllers.EquipmentLibraryController.Base64ToImage(List`1 equipmentFiles) in C:\Users\CMTech-DEV\Documents\cmtech\fieldservice-api\src\CallCenter\FieldService.CallCenter.API\Controllers\EquipmentLibraryController.cs:line 331

Answer 1

由于 using 块，您在将 MemoryStream 传递给 FormFile 构造函数后隐式调用 Dispose。然后你 return 一个 FormFile 对象的列表，其中内部流都是 disposed.

FormFile 不会复制流的内容，而是（通过 ReferencedReadStream) calls methods like Stream.Read which (in the case of MemoryStream at least) will throw an exception if the stream has been closed——这是由于 Dispose.

您没有提供任何信息，例如堆栈跟踪，所以这是一个最好的猜测，但是删除 using 块应该足以解决这个问题。

private List<IFormFile> Base64ToImage(List<EquipmentFile> equipmentFiles)
{
    List<IFormFile> formFiles = new List<IFormFile>();
    foreach (var eqp in equipmentFiles)
    {
        
        byte[] bytes = Convert.FromBase64String(eqp.File);
        MemoryStream stream = new MemoryStream(bytes);
        
        IFormFile file = new FormFile(stream, 0, bytes.Length, eqp.Name, eqp.Name);
        formFiles.Add(file);
        
    }
    return formFiles;
}

尝试将 base64String 转换为 IFormFile 在 C# 中引发 SystemInvalidOperation 异常

Trying to convert a base64String into a IFormFile throws SystemInvalidOperation exception in C#

c#

asp.net-core

base64

iformfile