如何在Xamarin.Forms中接收来自服务器的响应 [英] How to receive response from server in Xamarin.Forms
问题描述
我创建了一个HTTP客户端，该客户端将数据发送到我的服务器.此数据将查询我的服务器，该服务器将返回JSON对象.如何从服务器接收JSON对象响应并将其插入数据库?
I have created an HTTP Client that sends data to my server. This data will query my server that will return a JSON object. How can I receive the JSON Object response from my server and insert it into my database?
下面的代码将向服务器发送 ContactID ，服务器将返回JSON对象如何从服务器获取JSON对象?我将在代码中添加什么?我已添加
The code below will send a ContactID to my server and my server will return a JSON Object How can I get the JSON Object from my server? What will I add to my code? I have added
var data = await response.Content.ReadAsStringAsync();
但我不知道如何进行.
try
{
var db = DependencyService.Get<ISQLiteDB>();
var conn = db.GetConnection();
var sql = "SELECT * FROM tblUser WHERE ContactID = '" + contact + "'";
var getUser = conn.QueryAsync<UserTable>(sql);
var resultCount = getUser.Result.Count;
//Check if the user has been sync
if (resultCount < 1)
{
try
{
syncStatus.Text = "Syncing user to server...";
var link = Constants.requestUrl + "Host=" + host + "&Database=" + database + "&Contact=" + contact + "&Request=8qApc8";
string contentType = "application/json";
JObject json = new JObject
{
{ "ContactID", contact }
};
HttpClient client = new HttpClient();
var response = await client.PostAsync(link, new StringContent(json.ToString(), Encoding.UTF8, contentType));
var data = await response.Content.ReadAsStringAsync();
if (response.IsSuccessStatusCode)
{
var content = await response.Content.ReadAsStringAsync();
var userresult = JsonConvert.DeserializeObject<IList<UserData>>(content);
var count = userresult.Count;
for (int i = 0; i < count; i++)
{
try
{
syncStatus.Text = "Syncing user to server...";
var item = userresult[i];
var contactID = item.ContactID;
var userID = item.UserID;
var userPassword = item.UserPassword;
var userType = item.UserType;
var userStatus = item.UserStatus;
var lastSync = item.LastSync;
var serverUpdate = item.ServerUpdate;
var mobileUpdate = item.MobileUpdate;
var user = new UserTable
{
ContactID = Convert.ToInt32(contactID),
UserID = userID,
UserPassword = userPassword,
UserType = userType,
UserStatus = userStatus,
LastSync = lastSync,
ServerUpdate = serverUpdate,
MobileUpdate = mobileUpdate
};
await conn.InsertAsync(user);
}
catch (Exception ex)
{
Console.Write("Syncing user error " + ex.Message);
}
}
}
}
catch (Exception ex)
{
Console.Write("Syncing User Error " + ex.Message);
}
}
我的PHP代码将使用从 Xamarin HTTP Client 收到的 ContactID 查询我的数据库.
My PHP code will query my database with the ContactID received from Xamarin HTTP Client.
$json_str = file_get_contents('php://input');
$json_obj = json_decode($json_str);
$ContactID = $json_obj->ContactID;
$sql = "SELECT * FROM tblUser WHERE ContactID = '$ContactID'";
$result = mysqli_query($conn, $sql);
$count = mysqli_num_rows($result);
if($count > 0){
while ($row = @mysqli_fetch_array($result)) {
$decr = CryptRC4(FromHexDump($row['UserPassword']), $key);
$ar[] = array(
'ContactID' => $row['ContactID'],
'UserID' => $row['UserID'],
'UserPassword' => $decr,
'UserType' => $row['UserType'],
'UserStatus' => $row['UserStatus'],
'LastSync' => $sync,
'ServerUpdate' => $row['ServerUpdate'],
'MobileUpdate' => $row['MobileUpdate']
);
print json_encode($ar);
//Update LastSync DateTime
$sql = "UPDATE tblUser SET LastSync = '$sync' WHERE ContactID = '$ContactID'";
mysqli_query($conn, $sql);
}
}
推荐答案
上面示例中的最后一条语句以字符串格式给出了json对象的列表.
Last statement in your example above gives list of json objects in string format.
var data = await response.Content.ReadAsStringAsync();
您需要将其转换回对象列表.为了让您的项目了解对象的定义，请创建一个具有公共属性的普通类(如下所示)
You need to convert that back to list of objects. To let your project know about definition of the object, create a plain class with public properties (Something like below)
public class UserLog
{
public int ContactId { get; set; }
public string Log { get; set; }
public DateTime LogDate { get; set; }
}
将 Newtonsoft.Json (由James Newton-King设计)添加到项目中的Nuget包中，以便可以使用json.
Add Newtonsoft.Json (by James Newton-King) Nuget package to your project so that you can work with json.
要将变量"data"的内容转换为UserLog对象的列表，请编写类似
To convert content of the variable 'data' into list of UserLog objects, write code like
var list = NewtonsoftUtil<IList<UserLog>>.DeserializeObject(data);
(在文件顶部添加using Newtonsoft.Json;)
请告诉我这是否有帮助.
Please let me know if this helps.
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