Question

我试图在asp.net核心中使用TempData但是我在TempData的get方法上得到一个空值。任何人都可以告诉我如何在asp.net核心中使用TempData

以下是我根据研究添加的内容。

Project.json文件

{
  "dependencies": {
    "Microsoft.NETCore.App": {
      "version": "1.0.1",
      "type": "platform"
    },
    "Microsoft.AspNetCore.Mvc": "1.0.1",
    "Microsoft.AspNetCore.Routing": "1.0.1",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.1",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0",
    "Microsoft.Extensions.Configuration.Json": "1.0.0",
    "Microsoft.Extensions.Logging": "1.1.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.Logging.Debug": "1.0.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
    "Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",
    "Microsoft.EntityFrameworkCore.Design": "1.1.0",
    "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0",
    "DataBase": "1.0.0-*",
    "UnitOfWork": "1.0.0-*",
    "ViewModel": "1.0.0-*",
    "Common": "1.0.0-*",
    "System.IdentityModel.Tokens.Jwt": "5.0.0",
    "Microsoft.AspNetCore.Authentication.JwtBearer": "1.0.0",
    "Microsoft.AspNetCore.Diagnostics": "1.0.0",
    "Microsoft.AspNetCore.StaticFiles": "1.0.0",
    "Microsoft.AspNetCore.Session": "1.1.0",
    "Microsoft.Extensions.Caching.Memory": "1.1.0"
  },

  "tools": {
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final",
    "Microsoft.EntityFrameworkCore.Tools.DotNet": "1.0.0-preview3-final",
    "Microsoft.AspNetCore.Razor.Tools": "1.0.0-preview2-final"
  },

  "frameworks": {
    "netcoreapp1.0": {
      "imports": [
        "dotnet5.6",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "**/*.cshtml",
      "appsettings.json",
      "web.config"
    ]
  },

  "scripts": {
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

start.cs文件

public void ConfigureServices(IServiceCollection services)
{
    services.AddMemoryCache();
    services.AddSession();
    // Add framework services.
    services.AddMvc();
    services.AddTransient<IMarketUOW, MarketUow>();
    services.AddTransient<ICategoryUow, CategoryUow>();
    services.AddTransient<IUserProfileUow, UserProfileUow>();
    services.AddTransient<IItemUow, ItemUow>();

    services.AddTransient(typeof(IGenericRepository<>), typeof(GenericRepository<>));
    var connection = Configuration.GetConnectionString("DefaultConnection");
    services.AddDbContext<EmakitiContext>(options => options.UseSqlServer(connection));
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    app.UseSession();
    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
        });
    }

这是tempdata的实现。当调用此方法时，我可以看到TempData中的值。

[HttpGet("{pageNumber}")]
public GenericResponseObject<List<MarketViewModel>> GetMarketList(int pageNumber)
{
    TempData["Currentpage"] = pageNumber;
    TempData.Keep("Currentpage");
    GenericResponseObject<List<MarketViewModel>> genericResponseObject = new GenericResponseObject<List<MarketViewModel>>();
    genericResponseObject.IsSuccess = false;
    genericResponseObject.Message = ConstaintStingValue.Tag_ConnectionFailed;
    try
    {
        var marketItem = _iMarketUow.GetMarketList(pageNumber);
        genericResponseObject.Data = marketItem.Item1;
        var totalPages = (int)Math.Ceiling((decimal)marketItem.Item2 / (decimal)10);
        genericResponseObject.TotalPage = totalPages;
        genericResponseObject.IsSuccess = true;
        genericResponseObject.Message = ConstaintStingValue.Tag_SuccessMessageRecord;
        genericResponseObject.Message = ConstaintStingValue.Tag_ConnectionSuccess;
    }
    catch (Exception exception)
    {
        genericResponseObject.IsSuccess = false;
        genericResponseObject.Message = exception.Message;
        genericResponseObject.ErrorCode = exception.HResult;
        genericResponseObject.ExceptionErrorMessage = exception.StackTrace;
    }
    return genericResponseObject;
}

但是下面的方法在临时数据中有空值。

[HttpPost]
public GenericResponseObject<List<MarketViewModel>> AddUpdateMarket([FromBody] MarketViewModel marketViewModel)
{
    GenericResponseObject<List<MarketViewModel>> genericResponseObject = new GenericResponseObject<List<MarketViewModel>>();
    genericResponseObject.IsSuccess = false;
    genericResponseObject.Message = ConstaintStingValue.Tag_ConnectionFailed;

    if (marketViewModel!= null && ModelState.IsValid)
    {
        try
        {
            _iMarketUow.AddUpdateMarketList(marketViewModel);
            genericResponseObject = GetMarketList(Convert.ToInt16(TempData.Peek("Currentpage")));
        }
        catch (Exception exception)
        {
            genericResponseObject.IsSuccess = false;
            genericResponseObject.Message = exception.Message;
            genericResponseObject.ErrorCode = exception.HResult;
            genericResponseObject.ExceptionErrorMessage = exception.StackTrace;
        }
    }
    else
    {
        genericResponseObject.Message = ConstaintStingValue.Tag_InputDataFormatNotMatch;
    }
    return genericResponseObject;
}

以下是调试会话的图像

Answer 1

迁移到ASP Core 2.1之后，出现了此问题，并在工作了一天后找到了解决方案：

在Startup.Configure（）中 In [312]: df1['label'] = df1.merge(df2[['c1', 'c2']], how='left', indicator=True )['_merge'].eq('both').astype(int) In [313]: df1 Out[313]: c1 c2 label 0 dr123 di878 0 1 dr987 di082 1 2 dr751 di715 1 3 dr156 di083 0应该在In [88]: cols = ['c1', 'c2'] In [89]: mapper = {tuple(x[cols]) for _, x in df2.iterrows()} In [90]: df1.apply(lambda x: tuple(x[['c1', 'c2']]) in mapper, axis=1).astype(int) Out[90]: 0 0 1 1 2 1 3 0 dtype: int32之后

Answer 2

请将您的所有软件包升级到相同版本的1.1.0添加缓存服务。以下是在TempData

中使用Asp.Net Core所需的内容

<强> Project.json

"Microsoft.AspNetCore.Session": "1.1.0"

这是Startup.cs文件。 - ConfigureServices方法

public void ConfigureServices(IServiceCollection services)
{
     services.AddMemoryCache();
     services.AddSession();
     services.AddMvc();
}

和配置方法。

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    app.UseSession();
        app.UseMvc(routes =>
        {
            routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
    });
}

现在尝试使用TempData，它会起作用。

您可以使用设置ASPNETCORE_ENVIRONMENT =开发环境变量来设置环境。

PS

ASP.NET Core MVC公开TempData上的Controller属性。 TempData可用于存储瞬态数据，该瞬态数据仅需要在当前请求之后针对单个请求可用。

当读取TempDataDictionary中的对象时，将在该请求结束时将其标记为删除。

Peek和Keep方法允许您读取值而不将其标记为删除。假设我们回到第一个将值保存到TempData的请求。

使用Peek，您只需一次调用就可以获得值，而不会将其标记为删除。

//second request, PEEK value so it is not deleted at the end of the request
object value = TempData.Peek("value");

//third request, read value and mark it for deletion
object value = TempData["value"];

使用Keep指定要保留的标记为删除的密钥。检索对象以及稍后将其保存为删除是2个不同的调用。

//second request, get value marking it from deletion
object value = TempData["value"];
//later on decide to keep it
TempData.Keep("value");

//third request, read value and mark it for deletion
object value = TempData["value"];

Answer 3

official docs中所述的中间件顺序没有问题，即：

异常/错误处理
HTTP严格传输安全协议
HTTPS重定向
静态文件服务器
Cookie政策执行
身份验证
会话
MVC

但是，当我们使用Cookie策略实施（UseCookiePolicy）时，仅将要发送到浏览器的必需 cookie和来自Tempdata提供程序的Cookie都不是必需的，因此出现了问题。因此，我们必须根据official documentation将其设置为必不可少：

Tempdata提供程序cookie不是必需的。如果禁用了跟踪，则Tempdata提供程序将无法运行。要在禁用跟踪时启用Tempdata提供程序，请在Startup.ConfigureServices
中将TempData cookie标记为必不可少的。

// The Tempdata provider cookie is not essential. Make it essential
// so Tempdata is functional when tracking is disabled.
services.Configure<CookieTempDataProviderOptions>(options => {
   options.Cookie.IsEssential = true;
});

添加这些行应该可以解决您的问题，而无需重新排序中间件。

asp.net核心中的TempData null

3 个答案: