C# 如何处理来自httpclient的数据
我正在开发一个新的WindowsPhone8应用程序。我正在连接一个返回有效json数据的Web服务。我正在使用longlistselector显示数据。当我在GetAccountList()中使用字符串json时,这可以正常工作;但是当从DataServices类接收数据时,我得到一个错误“不能隐式地将类型'System.Threading.Tasks.Task'转换为字符串”。不知道出了什么问题。欢迎任何帮助。谢谢 DataServices.csC# 如何处理来自httpclient的数据,c#,json,mvvm,windows-phone-8,asynchttpclient,C#,Json,Mvvm,Windows Phone 8,Asynchttpclient,我正在开发一个新的WindowsPhone8应用程序。我正在连接一个返回有效json数据的Web服务。我正在使用longlistselector显示数据。当我在GetAccountList()中使用字符串json时,这可以正常工作;但是当从DataServices类接收数据时,我得到一个错误“不能隐式地将类型'System.Threading.Tasks.Task'转换为字符串”。不知道出了什么问题。欢迎任何帮助。谢谢 DataServices.cs public async stati
public async static Task<string> GetRequest(string url)
{
HttpClient httpClient = new HttpClient();
await Task.Delay(250);
HttpResponseMessage response = await httpClient.GetAsync(url);
response.EnsureSuccessStatusCode();
string responseBody = await response.Content.ReadAsStringAsync();
Debug.WriteLine(responseBody);
return await Task.Run(() => responseBody);
}
public static List<AccountModel> GetAccountList()
{
string json = DataService.GetRequest(url);
//string json = @"{'accounts': [{'id': 1,'created': '2013-10-03T16:17:13+0200','name': 'account1 - test'},{'id': 2,'created': '2013-10-03T16:18:08+0200','name': 'account2'},{'id': 3,'created': '2013-10-04T13:23:23+0200','name': 'account3'}]}";
List<AccountModel> accountList = new List<AccountModel>();
var deserialized = JsonConvert.DeserializeObject<IDictionary<string, JArray>>(json);
JArray recordList = deserialized["accounts"];
foreach (JObject record in recordList)
{
accountList.Add(new AccountModel(record["name"].ToString(), record["id"].ToString()));
}
return accountList;
}
公共异步静态任务GetRequest(字符串url)
{
HttpClient HttpClient=新HttpClient();
等待任务。延迟(250);
HttpResponseMessage response=等待httpClient.GetAsync(url);
response.EnsureSuccessStatusCode();
string responseBody=wait response.Content.ReadAsStringAsync();
Debug.WriteLine(responseBody);
返回等待任务。运行(()=>ResponseBy);
}
AccountViewModel.cs
public async static Task<string> GetRequest(string url)
{
HttpClient httpClient = new HttpClient();
await Task.Delay(250);
HttpResponseMessage response = await httpClient.GetAsync(url);
response.EnsureSuccessStatusCode();
string responseBody = await response.Content.ReadAsStringAsync();
Debug.WriteLine(responseBody);
return await Task.Run(() => responseBody);
}
public static List<AccountModel> GetAccountList()
{
string json = DataService.GetRequest(url);
//string json = @"{'accounts': [{'id': 1,'created': '2013-10-03T16:17:13+0200','name': 'account1 - test'},{'id': 2,'created': '2013-10-03T16:18:08+0200','name': 'account2'},{'id': 3,'created': '2013-10-04T13:23:23+0200','name': 'account3'}]}";
List<AccountModel> accountList = new List<AccountModel>();
var deserialized = JsonConvert.DeserializeObject<IDictionary<string, JArray>>(json);
JArray recordList = deserialized["accounts"];
foreach (JObject record in recordList)
{
accountList.Add(new AccountModel(record["name"].ToString(), record["id"].ToString()));
}
return accountList;
}
公共静态列表GetAccountList()
{
字符串json=DataService.GetRequest(url);
//字符串json=@“{'accounts':[{'id':1,'created':'2013-10-03T16:17:13+0200','name':'account1-test'},{'id':2,'created':'2013-10-03T16:18:08+0200','name':'account2},{'id':3,'created':'2013-10-04T13:23:23+0200','name':'account3'}”;
List accountList=新列表();
var deserialized=JsonConvert.DeserializeObject(json);
JArray recordList=反序列化[“帐户”];
foreach(记录列表中的作业对象记录)
{
accountList.Add(新的AccountModel(记录[“name”].ToString(),记录[“id”].ToString());
}
返回帐户列表;
}
更新:我对它做了一点小小的修改,现在它就像一个魔咒。谢谢你的帮助!
DataServices.cs
//GET REQUEST
public async static Task<string> GetAsync(string url)
{
var httpClient = new HttpClient();
var response = await httpClient.GetAsync(url);
string content = await response.Content.ReadAsStringAsync();
return content;
}
//获取请求
公共异步静态任务GetAsync(字符串url)
{
var httpClient=新的httpClient();
var response=wait-httpClient.GetAsync(url);
string content=wait response.content.ReadAsStringAsync();
返回内容;
}
AccountViewModel.cs
public async void LoadData()
{
this.Json = await DataService.GetAsync(url);
this.Accounts = GetAccounts(Json);
this.AccountList = GetAccountList(Accounts);
this.IsDataLoaded = true;
}
public static IList<AccountModel> GetAccounts(string json)
{
dynamic context = JObject.Parse(json);
JArray deserialized = (JArray)JsonConvert.DeserializeObject(context.results.ToString());
IList<AccountModel> accounts = deserialized.ToObject<IList<AccountModel>>();
return accounts;
}
public static List<AlphaKeyGroup<AccountModel>> GetAccountList(IList<AccountModel> Accounts)
{
List<AlphaKeyGroup<AccountModel>> accountList = AlphaKeyGroup<AccountModel>.CreateGroups(Accounts,
System.Threading.Thread.CurrentThread.CurrentUICulture,
(AccountModel s) => { return s.Name; }, true);
return accountList;
}
public异步void LoadData()
{
this.Json=await-DataService.GetAsync(url);
this.Accounts=GetAccounts(Json);
this.AccountList=GetAccountList(Accounts);
this.IsDataLoaded=true;
}
公共静态IList GetAccounts(字符串json)
{
动态上下文=JObject.Parse(json);
JArray反序列化=(JArray)JsonConvert.DeserializeObject(context.results.ToString());
IList accounts=反序列化的.ToObject();
归还账户;
}
公共静态列表GetAccountList(IList帐户)
{
List accountList=AlphaKeyGroup.CreateGroups(帐户,
System.Threading.Thread.CurrentThread.CurrentUICulture,
(AccountModels)=>{return s.Name;},true);
返回帐户列表;
}
那一行是你的问题:
return await Task.Run(() => responseBody);
你试过了吗
return responseBody;
也试试这个:
public async static List<AccountModel> GetAccountList()
{
string json = await DataService.GetRequest(url);
...
}
public异步静态列表GetAccountList()
{
string json=wait DataService.GetRequest(url);
...
}
这里有几件事。首先是错误
无法将类型“System.Threading.Tasks.Task”隐式转换为字符串
此错误来自对DataService.GetRequest(url)
的调用。此方法确实返回字符串。Tt返回一个字符串,其中T是字符串。有许多方法可以使用此方法的结果。第一个(最好的/最新的)是等待对该方法的调用
进行此更改需要将async
键盘添加到方法中
public async static List<AccountModel> GetAccountList()
现在来看GetResult方法。使用异步/等待模式需要从方法返回任务。即使返回类型是Task,代码也应该返回T
return responseBody;
下面是一个关于从异步方法返回任务的示例。仍然相同。它在GetAccountList()中的“string json=DataService.GetRequest(url);”上给出了错误。是的,它将在那里给出错误,原因是异步。但是请在GetReuquest方法中设置一个断点,并告诉我们“真的”异常在哪里:)