在类型“System.Collections.Generic.List`1[Portal.Models.FileDataModel]”中发现了多个接受所有给定参数类型的构造函数

Question

我正在使用带有 EF Core 和 Azure 存储（文件存储）的 ASP.NET Core 3.1。我正在使用 Microsoft.Azure.Storage.File version 11.2.2 处理 Azure 存储文件。

除了依赖注入 (DI) 问题之外，我不确定这个错误到底指的是什么？

我遇到的大多数引用此错误消息的文章或 SO 文章都建议使用 DI，但是当他们在 Startup.cs 中注入它时，他们有一个接口来伴随他们的注入。我没有。

我正在为这个视图使用 Razor 页面。这段代码以前是为 MVC 视图编写的，我正在尝试将其转换为内聚。见原帖HERE。 MVC 中的项目可以正常工作。我应该放弃尝试在 Razor 页面中执行所有这些操作并在我的整个项目中使用 MVC，还是我遗漏了一个明显的问题？？

这是我的设置：

namespace AzureFileShare.Pages.Files
{
    public class IndexModel : PageModel
    {
        private readonly IConfiguration _configuration;

        public IndexModel(
            IConfiguration configuration)
        {
            _configuration = configuration;
            
        }
        public async Task<IList<FileModel>> OnGetAsync()
        {
            string fileStorageConnection = _configuration.GetValue<string>("fileStorageConnection");
            CloudStorageAccount storageAccount = CloudStorageAccount.Parse(fileStorageConnection);
            CloudFileShare share = storageAccount.CreateCloudFileClient().GetShareReference("payreports");
            CloudFileDirectory root = share.GetRootDirectoryReference();
            CloudFileDirectory dir = root.GetDirectoryReference(@"E000002/stubs");

            // list all files in the directory
            var fileData =  await list_subDir(dir);
            return fileData;

        }
        
        public static async Task<List<FileModel>> list_subDir(CloudFileDirectory fileDirectory)
        {
            var fileData = new List<FileModel>();
           
            FileContinuationToken token = null;
            do
            {
                FileResultSegment resultSegment = await fileDirectory.ListFilesAndDirectoriesSegmentedAsync(token);
                foreach (var fileItem in resultSegment.Results)
                {
                    if (fileItem is CloudFile)
                    {
                        var cloudFile = (CloudFile) fileItem;
                        //get the cloudfile's properties and metadata
                        await cloudFile.FetchAttributesAsync();

                        // Add properties to FileDataModel 
                        fileData.Add(new FileModel()
                        {
                            FileName = cloudFile.Name,
                            Size = Math.Round((cloudFile.Properties.Length / 1024f), 2).ToString(),
                            DateModified = DateTime.Parse(cloudFile.Properties.LastModified.ToString()).ToLocalTime().ToString()
                        });
                    }

                    if (fileItem is CloudFileDirectory)
                    {
                        var cloudFileDirectory = (CloudFileDirectory)fileItem;
                        await cloudFileDirectory.FetchAttributesAsync();
                        
                        //list files in the directory
                        var result = await list_subDir(cloudFileDirectory);
                        fileData.AddRange(result);
                    }
                    // get the FileContinuationToken to check if we need to stop the loop
                    token = resultSegment.ContinuationToken;
                }
            } while (token != null);

            return fileData.OrderByDescending(o => Convert.ToDateTime( o.DateModified)).ToList();
            
        }
    }
}

型号

    public class FileModel
    {
        public string FileName { get; set; }
        public string Size { get; set; }
        public string DateModified { get; set; }
    }

appsettings.json

{
  "ConnectionStrings": {
    "fileStorageConnection": "DefaultEndpointsProtocol=https;AccountName=navraereports;AccountKey=REMOVEDFORPUBLIC;EndpointSuffix=core.windows.net"
  }

}

@page
@model List<FileModel>

@{
    ViewData["Title"] = "Download Pay Stub Copies";
}

<h1>Pay Stub Copies</h1>
<table class="table table-bordered">
    <thead>
        <tr>
            <th>File Name</th>
            <th>File Size</th>
            <th>File Date</th>
            <th>Download</th>
        </tr>
    </thead>
    <tbody>
        @foreach (var data in Model)
        {
            <tr>
                <td>@data.FileName</td>
                <td>@data.Size</td>
                <td>@data.DateModified</td>
                <td>
                    <a class="btn btn-primary"
                       href="/File/DownloadStub?id=@data.FileName">Download</a>
                </td>
            </tr>
        }
    </tbody>
</table>

堆栈跟踪：

System.InvalidOperationException: Multiple constructors accepting all given argument types have been found in type 'System.Collections.Generic.List`1[AzureFileShare.FileModel]'. There should only be one applicable constructor.
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.TryFindMatchingConstructor(Type instanceType, Type[] argumentTypes, ConstructorInfo& matchingConstructor, Nullable`1[]& parameterMap)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.FindApplicableConstructor(Type instanceType, Type[] argumentTypes, ConstructorInfo& matchingConstructor, Nullable`1[]& parameterMap)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.CreateFactory(Type instanceType, Type[] argumentTypes)
   at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.DefaultPageModelActivatorProvider.CreateActivator(CompiledPageActionDescriptor actionDescriptor)
   at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.DefaultPageModelFactoryProvider.CreateModelFactory(CompiledPageActionDescriptor descriptor)
   at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvokerProvider.CreateCacheEntry(ActionInvokerProviderContext context, FilterItem[] cachedFilters)
   at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvokerProvider.OnProvidersExecuting(ActionInvokerProviderContext context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionInvokerFactory.CreateInvoker(ActionContext actionContext)
   at Microsoft.AspNetCore.Mvc.Routing.ActionEndpointFactory.<>c__DisplayClass7_0.<CreateRequestDelegate>b__0(HttpContext context)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext)
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Answer 1

更新

在 Razor 视图中，替换

@model List<FileModel>

与

@model AzureFileShare.Pages.Files.IndexModel 

在IndexModel.cshtml.cs 中，您需要一个新属性来获取结果

public List<FileModel> FileModels { get; private set; } = new List<FileModel>();

除了更改签名之外，您还需要在方法内部进行一些更改。

public async Task OnGetAsync()
    {
        string fileStorageConnection = _configuration.GetValue<string>("fileStorageConnection");
        CloudStorageAccount storageAccount = CloudStorageAccount.Parse(fileStorageConnection);
        CloudFileShare share = storageAccount.CreateCloudFileClient().GetShareReference("payreports");
        CloudFileDirectory root = share.GetRootDirectoryReference();
        CloudFileDirectory dir = root.GetDirectoryReference(@"E000002/stubs");

        // list all files in the directory
        FileModels = await list_subDir(dir);
    }

最后，回到 Razor 视图并更改

@foreach (var data in Model)

知道

@foreach (var data in Model.FileModels)

---

请尝试更换

fileData.OrderByDescending(o => Convert.ToDateTime( o.DateModified));

与

return fileData.OrderByDescending(o => Convert.ToDateTime( o.DateModified)).ToList();

并删除

return fileData;

从正下方。

你也应该替换

Stream fileStream = file.OpenReadAsync().Result;

与

Stream fileStream = await file.OpenReadAsync();

替换

await file.DownloadToStreamAsync(memoryStream);

与

await file.DownloadToStreamAsync(new MemoryStream());

并删除

MemoryStream memoryStream = new MemoryStream();