如何从异步 function C# 返回字符串而不是 SYSTEM.THREADING.TASK.TASK`1[SYSTEM.STRING]

Question

I have a SQLite database within the Xamarin application I am building which stores and retrieves information about animals. One of my SQLite async functions is to get the diet of the animal based upon the animal name passed into this function. From this function I am trying to return a string which will be the found diet, but at the minute it is is returning the value SYSTEM.THREADING.TASK.TASK`1[SYSTEM.STRING]. I have tried all of my ideas, but nothing is working for this. Any help would be appreciated.

Animal class:

    public class Animal
{
    [PrimaryKey, AutoIncrement]
    public int ID { get; set; }
    [NotNull]
    public string Name { get; set; }
    [NotNull]
    public string Diet { get; set; }
    [NotNull]
    public string Markings { get; set; }
    [NotNull]
    public string Ecosystem { get; set; }

}

}

SQLite function for retrieving the diet:

public async Task<string> getAnimalDiet(string animalName)
    {
       
            Animal a =  await Database.Table<AnimalInfo>().Where(x => x.Name == animalName).FirstOrDefaultAsync();
            return await Task.FromResult(a.Diet);

    }

Calling this function within my Xamarin (where it returns SYSTEM.THREADING.TASK.TASK`1[SYSTEM.STRING] not the diet as a string)

void getDiet(List<string> final)
    {  
        List<string> found = new List<string>();
        if (final.Count > 0)
        {

            foreach(string animal in final)
            {

              found.Add(App.Database.getAnimalDiet(animal).ToString());

            }

            foreach(string entry in found)
            {
                NewButtonCreation(entry);
            }


        }
    }

Answer 1

You can replace

return await Task.FromResult(a.Diet);

with

return a.Diet;

for the same result.

Your problem is not with how you wrote getAnimalDiet() but with how you call it, it needs to be awaited:

  //found.Add(App.Database.getAnimalDiet(animal).ToString());
  found.Add(await App.Database.getAnimalDiet(animal));

but that means that void getDiet( ) has to become async Task getDiet( ) or async void getDiet( )

Prefer async Task and work your way up. Only toplevel methods and eventhandlers should be async void . Google for the differences and consequences.