程式筆記

測試程式

        private async Task<string> GetE0501JsonStringAsync()
        {
            HttpClient _httpClient = new HttpClient();


            Logger.Info($"1={Thread.CurrentThread.ManagedThreadId}");
            
            var jsonString =
                 await _httpClient.GetStringAsync(@"https://localhost:44300/api/v1/e0501/");

            Logger.Info($"2={Thread.CurrentThread.ManagedThreadId}");
            
            return jsonString;
        }

        public async Task<ActionResult> ImportByUrl(int id)
        {
            Logger.Info($"0={Thread.CurrentThread.ManagedThreadId}");

            var e0501 = GetE0501JsonString().Result;
                         
            Logger.Info($"3={Thread.CurrentThread.ManagedThreadId}");
        }

執行結果

2023/10/19 13:36:11
0=5
2023/10/19 13:36:13
1=5

修改程式, 在呼叫處也加上await

        public async Task<ActionResult> ImportByUrl(int id)
        {
            Logger.Info($"0={Thread.CurrentThread.ManagedThreadId}");

            var e0501 = await GetE0501JsonString();
                         
            Logger.Info($"3={Thread.CurrentThread.ManagedThreadId}");
        }

執行結果

2023/10/19 11:29:11
0=8
2023/10/19 11:30:21
1=8
2023/10/19 11:30:27
2=24				
--> HttpClient create new thread. 
所以呼叫處也要await, 因為old thread已經往下go.
2023/10/19 11:30:33
3=24