我正在尝试使用异步控制器操作,以遵循典型身份AccountController
代码的模式,但如果我直接访问该页面,则会出现以下错误(如果我通过登录后重定向):
The specified parameter type 'System.Threading.Tasks.Task`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' is not valid. Only scalar types, such as System.Int32, System.Decimal, System.DateTime, and System.Guid, are supported.
Parameter name: item
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentOutOfRangeException: The specified parameter type 'System.Threading.Tasks.Task`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' is not valid. Only scalar types, such as System.Int32, System.Decimal, System.DateTime, and System.Guid, are supported.
Parameter name: item
Source Error:
Line 107: public async Task<Candidate> CurrentCandidate()
Line 108: {
Line 109: return await this.Context.Candidate.FindAsync(this.CurrentCandidateId());
Line 110: }
Line 111:
public async Task<ActionResult> Index(int id = 0)
{
// Get current user
var candidate = await base.CurrentCandidate();
if (candidate != null)
{
ApplicationUser user = await UserManager.FindByIdAsync(candidate.CandidateGuid.ToString());
}
return View();
}
/// <summary>
/// Return the current logged-in candidate, based on the current candidate id
/// </summary>
public async Task<Candidate> CurrentCandidate()
{
return await this.Context.Candidate.FindAsync(this.CurrentCandidateId());
}
其中Context是典型的EF6数据库上下文。
public async Task<int> CurrentCandidateId()
{
if (User.Identity.IsAuthenticated)
{
var user = await UserManager.FindByIdAsync(User.Identity.GetUserId());
if (user != null)
{
return user.CandidateId.GetValueOrDefault(0);
}
}
return 0;
}
我在俯瞰什么?我是新的异步编码风格的新手,所以请随时教我:)
答案 0 :(得分:5)
您的CurrentCandidateId
函数为async
并返回Task<int>
。 DbSet.FindAsync
采用任何类型的对象,但肯定不知道如何处理Task<int>
。您需要await
执行该任务,并将其结果传递给FindAsync
。
public async Task<Candidate> CurrentCandidate()
{
return await this.Context.Candidate
.FindAsync(await this.CurrentCandidateId());
// ^^^^^
}