Xamarin JSON反序列化

Xamarin JSON Deserialize

我创建了一个httpwebrequest来检查用户的用户名和密码是否正确。如果用户的用户名和密码正确，它将返回一个带有用户contactID的JSON数组。我试图反序列化JSON，但未能获得实际数据。我想获取联系人ID并将数据发送到下一页的变量。

用户名和密码正确时JSON的输出：

[{"ContactID":"1"}]

我的代码：

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using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Net;
using System.Text;
using System.Windows.Input;
using TBSMobileApplication.Data;
using TBSMobileApplication.View;
using Xamarin.Essentials;
using Xamarin.Forms;

namespace TBSMobileApplication.ViewModel
{
public class LoginPageViewModel : INotifyPropertyChanged
{
void OnProperyChanged(string PropertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(PropertyName));
}

public string username;
public string password;

public string Username
{
get { return username; }
set
{
username = value;
OnProperyChanged(nameof(Username));
}
}

public string Password
{
get { return password; }
set
{
password = value;
OnProperyChanged(nameof(Password));
}
}

public ICommand LoginCommand { get; set; }

public LoginPageViewModel()
{
LoginCommand = new Command(OnLogin);
}

public void OnLogin()
{
if (string.IsNullOrEmpty(Username) || string.IsNullOrEmpty(Password))
{
MessagingCenter.Send(this,"Login Alert", Username);
}
else
{
var current = Connectivity.NetworkAccess;

if (current == NetworkAccess.Internet)
{
var link ="http://192.168.1.25:7777/TBS/test.php?User=" + Username +"&Password=" + Password;
var request = HttpWebRequest.Create(string.Format(@link));
request.ContentType ="application/json";
request.Method ="GET";

using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
{
if (response.StatusCode != HttpStatusCode.OK)
{
Console.Out.WriteLine("Error fetching data. Server returned status code: {0}", response.StatusCode);
}
else
{
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
var content = reader.ReadToEnd();

if (content.Equals("[]") || string.IsNullOrWhiteSpace(content) || string.IsNullOrEmpty(content))
{
MessagingCenter.Send(this,"Http", Username);
}
else
{
var usr = JsonConvert.DeserializeObject(content);
App.Current.MainPage.Navigation.PushAsync(new DatabaseSyncPage(), true);
}
}
}
}
}
else
{
MessagingCenter.Send(this,"Not Connected", Username);
}
}
}

public event PropertyChangedEventHandler PropertyChanged;
}
}

修改代码else块，如下所示

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if (content.Equals("[]") || string.IsNullOrWhiteSpace(content) || string.IsNullOrEmpty(content))
{
MessagingCenter.Send(this,"Http", Username);
}
else
{
var response = JsonConvert.DeserializeObject<List<LoggedInUser>>(content);
var contactId=response[0].ContactID;
//response have your ContactID value. Try to debug & see.
App.Current.MainPage.Navigation.PushAsync(new DatabaseSyncPage(), true);
}

创建另一个公共类来反序列化响应

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public class LoggedInUser
{
public string ContactID { get; set; }
}

如果结果中有超过1条记录(正如您在下面的评论中所问的那样)你可以通过循环得到它们

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for (int i = 0; i < response.Count; i++)
{
var item = response[i];
var contactId = item.ContactId;
}

希望对你有帮助。