我不确定能解决什么问题。我正在开发一个简单的测试，即将图像上传到我的Azure存储。但是，该文件存在，但在存储上为null。看起来上传不起作用，我不明白为什么。我有这个控制器：
Create.cshtml.cs
namespace CoreWebApp.Pages
{
public class CreateModel : PageModel
{
public void OnGet()
{
}
[BindProperty]
public CountryForm Country { get; set; }
[HttpPost("CreateCountry")]
public async Task<IActionResult> OnPostAsync(IFormFile file)
{
if (!ModelState.IsValid)
return Page();
/*var errors = ModelState.Where(x => x.Value.Errors.Count > 0)
.Select(x => new { x.Key, x.Value.Errors })
.ToArray();*/
var filePath = Path.GetTempFileName();
using (var stream = new FileStream(filePath, FileMode.Create))
{
await file.CopyToAsync(stream);
string pictureUrl = Shared.AzureCloud.AzureCDN.GetAzureCDNInstance().UploadFile(stream, file.Name);
try
{
if (pictureUrl != null)
Shared.Database.SqlAction.CountriesTable.AddCountry(new Country()
{
Name = Country.Name,
PictureUrl = pictureUrl
});
}
catch (Exception e)
{
Console.WriteLine(e);
}
}
return Page();
}
}
}
Create.cshtml
@page
@model CreateModel
@{
ViewData["Title"] = "Create";
}
<div class="container">
<div class="row">
<div class="col-lg-3" style="background-color:#FF0000;">
<h4>Add a Country</h4>
<form class="form form-horizontal" method="post" enctype="multipart/form-data" asp-controller="Create">
<div asp-validation-summary="All"></div>
<div class="row">
<div class="col-md-12">
<div class="form-group">
<label asp-for="Country.Name" class="col-md-3 right">Name:</label>
<div class="col-md-9">
<input asp-for="Country.Name" class="form-control" />
<span asp-validation-for="Country.Name"></span>
</div>
</div>
<div class="form-group">
<div class="col-md-10">
<p>Picture</p>
<input type="file" name="file" />
</div>
</div>
</div>
</div>
<div class="row">
<div class="col-md-12">
<button type="submit">Create</button>
</div>
</div>
</form>
</div>
<div class="col-*-*"></div>
</div>
<div class="row">
<div class="col-*-*"></div>
<div class="col-*-*"></div>
<div class="col-*-*"></div>
</div>
<div class="row">
...
</div>
</div>
我的AzureCDN类只是一个封装：
namespace Shared.AzureCloud
{
public class AzureCDN
{
private CloudStorageAccount storageAccount { get; set; }
private CloudBlobClient blobClient { get; set; }
private CloudBlobContainer container { get; set; }
private CloudBlockBlob blockBlob { get; set; }
/// <summary>
/// Initializes a new instance of the <see cref="T:Shared.AzureCloud.AzureCDN"/> class.
/// </summary>
public AzureCDN()
{
// Retrieve storage account from connection string.
storageAccount = CloudStorageAccount.Parse(String.Format("DefaultEndpointsProtocol=https;AccountName={0};AccountKey={1}",
Shared.Constants.Azure.AccountName, Shared.Constants.Azure.AccountKey));
// Create the blob client.
blobClient = storageAccount.CreateCloudBlobClient();
// Retrieve a reference to a container.
container = blobClient.GetContainerReference("eyesmedias");
// Create the container if it doesn't already exist.
container.CreateIfNotExistsAsync();
}
/// <summary>
/// Uploads the file.
/// </summary>
/// <returns>The file.</returns>
/// <param name="fileStream">File stream.</param>
/// <param name="fileName">File name.</param>
public string UploadFile(FileStream fileStream, string fileName)
{
// Retrieve reference to a blob named {name}.
blockBlob = container.GetBlockBlobReference(fileName);
try
{
// Create or overwrite the {name} "blob with contents from a local file.
blockBlob.UploadFromStreamAsync(fileStream);
return (blockBlob.Uri.ToString());
} catch (Exception e)
{
throw e;
}
}
#region Singletown part
/// <summary>
/// The instance.
/// </summary>
private static AzureCDN Instance = null;
/// <summary>
/// Gets the azure CDN Instance.
/// </summary>
/// <returns>The azure CDNI nstance.</returns>
public static AzureCDN GetAzureCDNInstance()
{
if (Instance == null)
{
Instance = new AzureCDN();
}
return (Instance);
}
/// <summary>
/// Sets the azure CDN Instance.
/// </summary>
/// <param name="instance">Instance.</param>
public static void SetAzureCDNInstance(AzureCDN instance)
{
Instance = instance;
}
/// <summary>
/// Init this instance.
/// </summary>
public static void Init()
{
Instance = new AzureCDN();
}
#endregion
}
}
问题是，blockBlob.UploadFromStreamAsync(fileStream);似乎没问题，因为它没有抛出任何异常并且路径被很好地返回，但是，即使文件在我的CDN上，它也是空的，不像文件我我在我的Mac上从ASP.NET页面中选择。
我是ASP.NET的新手（我在2天前开始），也欢迎从网络应用程序ASP.NET上传文件的建议：）
感谢您的帮助！
答案 0 :(得分：1)
将文件复制到流后，您必须使用stream.Seek(0, SeekOrigin.Begin);再次将流的位置设置为开头（请参阅docs），以便上传实际内容：
[HttpPost("CreateCountry")]
public async Task<IActionResult> OnPostAsync(IFormFile file)
{
if (!ModelState.IsValid)
return Page();
/*var errors = ModelState.Where(x => x.Value.Errors.Count > 0)
.Select(x => new { x.Key, x.Value.Errors })
.ToArray();*/
var filePath = Path.GetTempFileName();
using (var stream = new FileStream(filePath, FileMode.Create))
{
await file.CopyToAsync(stream);
stream.Seek(0, SeekOrigin.Begin);
string pictureUrl = Shared.AzureCloud.AzureCDN.GetAzureCDNInstance().UploadFile(stream, file.Name);
try
{
if (pictureUrl != null)
Shared.Database.SqlAction.CountriesTable.AddCountry(new Country()
{
Name = Country.Name,
PictureUrl = pictureUrl
});
}
catch (Exception e)
{
Console.WriteLine(e);
}
}
return Page();
}
如果你不这样做，那么你要上传当前位置已经在最后的流，这样就会上传一个空文件。