无法将类型'bool'隐式转换为'system.threading.tasks.task bool'

I have this error: "Cannot implicitly convert type 'bool' to 'system.threading.tasks.task bool'" in my service implementation code. Could you correct my code please.

我有这样的错误：“不能在我的服务实现代码中隐式地将类型'bool'转换为'system.threading.tasks.task bool'”。你能纠正我的代码吗？

public Task<bool> login(string usn, string pwd)
    {
        DataClasses1DataContext auth = new DataClasses1DataContext();
        var message = from p in auth.Users
                      where p.usrName == usn && p.usrPass == pwd
                      select p;
        if (message.Count() > 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }

2 个解决方案

#1

You need to be specific whether you want this operation happen asynchronously or not.

您需要具体说明是否要将此操作异步发生。

As an example for Async Operation :

作为异步操作的示例：

public async Task<bool> login(string usn, string pwd)
{
    DataClasses1DataContext auth = new DataClasses1DataContext();
    var message = await (from p in auth.Users
                  where p.usrName == usn && p.usrPass == pwd
                  select p);
    if (message.Count() > 0)
    {
        return true;
    }
    else
    {
        return false;
    }
}

If you don't need it to be an Async operation, try this:

如果您不需要它作为异步操作，请尝试以下操作：

public bool login(string usn, string pwd)
{
    DataClasses1DataContext auth = new DataClasses1DataContext();
    var message = from p in auth.Users
                  where p.usrName == usn && p.usrPass == pwd
                  select p;
    if (message.Count() > 0)
    {
        return true;
    }
    else
    {
        return false;
    }
}

Note: async and await are compatible with .net 4.5 and C# 5.0 and more

注意：async和await与.net 4.5和C＃5.0及更多版本兼容

#2

If you add Task.FromResult, you can fake it into compiling and working even though your method is not async. I had to do this when hooking up Identity, which is all async, to a legacy back end.

如果添加Task.FromResult，即使您的方法不是异步，也可以将其伪装成编译和工作。我必须在将Identity（异步同步）连接到传统后端时执行此操作。

Example:

例：

public override Task<bool> IsEmailConfirmedAsync(string userId)
{
  var profile = UserProfileType.FetchUserProfile(AtlasBusinessObject.ClientId.ToString(), decimal.Parse(userId));
  Task.FromResult(profile.EmailAddress.NullIfEmpty() != null);
}

#1