System.InvalidOperationException：无法为 System.Threading.ExecutionContext& Context 创建 getter

Question

我有 Stocks 和 AppUsers 表以及 Portfolios 表，它们之间是多对多关系。我想获取投资组合的数据，但我的 API 遇到问题。它说：

Newtonsoft.Json.JsonSerializationException: Error getting value from 'Context' on 'System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1+AsyncStateMachineBox`1[System.Collections.Generic.List`1[api.Models.Stock],API.Repositories.Concrete.PortfolioRepository+<GetUserPortfolio>d__2]'.
 ---> System.InvalidOperationException: Could not create getter for System.Threading.ExecutionContext& Context. ByRef return values are not supported.
   at Newtonsoft.Json.Utilities.ReflectionDelegateFactory.CreateGet[T](MemberInfo memberInfo)
   at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue(Object target)
   --- End of inner exception stack trace ---
   at Newtonsoft.Json.Serialization.ExpressionValueProvider.GetValue(Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CalculatePropertyValues(JsonWriter writer, Object value, JsonContainerContract contract, JsonProperty member, JsonProperty property, JsonContract& memberContract, Object& memberValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
   at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType)
   at Newtonsoft.Json.JsonSerializer.Serialize(JsonWriter jsonWriter, Object value)
   at Microsoft.AspNetCore.Mvc.Formatters.NewtonsoftJsonOutputFormatter.WriteResponseBodyAsync(OutputFormatterWriteContext context, Encoding selectedEncoding)
   at Microsoft.AspNetCore.Mvc.Formatters.NewtonsoftJsonOutputFormatter.WriteResponseBodyAsync(OutputFormatterWriteContext context, Encoding selectedEncoding)
   at Microsoft.AspNetCore.Mvc.Formatters.NewtonsoftJsonOutputFormatter.WriteResponseBodyAsync(OutputFormatterWriteContext context, Encoding selectedEncoding)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResultFilterAsync>g__Awaited|30_0[TFilter,TFilterAsync](ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResultExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeResultFilters()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|20_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

我的控制器：

[HttpGet]
[Authorize]
public async Task<IActionResult> GetUserPortfolio()
{
    var username = User.GetUsername();
    var appUser = await userManager.FindByNameAsync(username);
    var userPortfolio = portfolioReposiotry.GetUserPortfolio(appUser);
    return Ok(userPortfolio);
}

我的仓库：

public class PortfolioRepository : IPortfolioRepository
{
    private readonly AppDbContext context;

    public PortfolioRepository(AppDbContext context)
    {
        this.context = context;
    }

    public async Task<List<Stock>> GetUserPortfolio(AppUser user)
    {
        var val = context.Portfolios.Where(u => u.AppUserId == user.Id)
            .Select(stock => new Stock
            {
                Id = stock.StockId,
                Symbol = stock.Stock.Symbol,
                CompanyName = stock.Stock.CompanyName,
                Purchase = stock.Stock.Purchase,
                LastDiv = stock.Stock.LastDiv,
                Industry = stock.Stock.Industry,
                MarketCap = stock.Stock.MarketCap
            });
        return await val.ToListAsync();
    }
}

不知道还需要什么吗？如果是的话请告诉我

我没有尝试任何解决方案，因为我不知道发生了什么。

Answer 1

System.InvalidOperationException：无法创建 getter System.Threading.ExecutionContext& 上下文

不知道还需要什么吗？如果是的话请告诉我

我没有尝试任何解决方案，因为我不知道发生了什么。

根据您的情况和描述，您遇到的错误可能有几个原因。

首先，确保 Stock 模型不包含任何可能导致序列化问题的属性。 Stock 模型或其相关类之一中可能有一个名为“Context”的属性。

此外，

GetUserPortfolio

方法是异步的，您正在正确等待其结果。但是，在 appUser 之后调用控制器中的

GetUserPortfolio

方法时，您没有维护异步链。

因此，为了修复您应该重构代码，如下所示：

[HttpGet]
[Authorize]
public async Task<IActionResult> GetUserPortfolio()
{
    var username = User.GetUsername();
    var appUser = await userManager.FindByNameAsync(username);
    var userPortfolio = await  portfolioReposiotry.GetUserPortfolio(appUser);
    return Ok(userPortfolio);
}

注意： 确保

User.GetUsername()

也保持相同的

asynchronous

链。