Object not awaitable when returning Task<object> instead of List

May 2, 2022

I have this method that should return only one Project object.
IntelliSense is telling me to update it to return a Task<List> but then I have to change the declaration of the property (I want to confirm that only one project is being returned, hence the .Result.First()
however I’m getting an error saying that Project is not awaitable.

 public async Task<Project> GetProjectDataAsync(int projectId)
        {
            return await _db.LoadData<Project, dynamic>("dbo.Sp_Get_Project_Data_By_ProjectId",
                new { projectId },
                ConnectionStringName,
                true).Result.First();
        }

this is the call:

 public Project Project { get; set; }
 public async Task OnGetAsync(int projectId)
        {
            Project = await _db.GetProjectDataAsync(projectId);

        }

If it worth noting, I’m using Dapper to connect to DB with the following definition for LoadData:

 public async Task<List<T>> LoadData<T, U>(string sqlStatement, U parameters, string connectionStringName, bool isStoredProcedure = false)
        {
            string connectionString = _config.GetConnectionString(connectionStringName)!;

            CommandType commandType = CommandType.Text;

            if (isStoredProcedure == true)
            {
                commandType = CommandType.StoredProcedure;
            }

            using (IDbConnection connection = new SqlConnection(connectionString))
            {
                var rows = await connection.QueryAsync<T>(sqlStatement, parameters, commandType: commandType);
                return rows.ToList();
            }
        }

>Solution :

Get rid of the .Result call. It’s essentially trying to make the asynchronous operation synchronous. (And then .First() is indeed not awaitable.)

The awaitable operation is _db.LoadData<Project, dynamic>(...), for example:

var data = await _db.LoadData<Project, dynamic>(
  "dbo.Sp_Get_Project_Data_By_ProjectId",
  new { projectId },
  ConnectionStringName,
  true
);
return data.First();

Or if you want to do it in one line, still await the call to LoadData and wrap that operation in parentheses:

return (await _db.LoadData<Project, dynamic>(
  "dbo.Sp_Get_Project_Data_By_ProjectId",
  new { projectId },
  ConnectionStringName,
  true
)).First();