Question

当用户从登录活动输入密码时将其发送到登录服务并等待登录服务中的布尔响应。但它给出上面的语法错误（我在代码中提到它）可以解决我的问题。我要等到服务响应进入我的登录活动

1.登录界面

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
namespace RetailAppShared
{
    public interface ILoginServices
    {
        bool AuthenticateUser (string passcode, Func<bool> function);
    }
}

2.登录服务

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Net;
using RestSharp;
using System.Threading.Tasks;
using Newtonsoft.Json;

namespace RetailAppShared
{
    public class LoginServices : ILoginServices
    {               
        public bool AuthenticateUser (string passcode, Func<bool> function)
        {

            try {
                RestClient _client = new RestClient ("https://www.example.com/app/class");
                var request = new RestRequest ("loginservice", Method.POST) {
                    RequestFormat = DataFormat.Json
                };
                var obj = new login ();
                obj.passcode = passcode;

                request.AddJsonBody (obj);
                request.AddHeader ("Content-type", "application/json");
                _client.ExecuteAsync (request, response => {
                    if (response.StatusCode == HttpStatusCode.OK) {
                        if (!string.IsNullOrEmpty (response.Content)) {
                            var objlog = JsonConvert.DeserializeObject<LoginModel> (response.Content);
                            flag = objlog.result.state == 1 ? true : false;

                            function (true);//error
                        } else
                            flag = false;                            
                    }

                });
            } catch (Exception ex) {
                Debug.WriteLine (@" ERROR {0}", ex.Message);
            }               
        }    

    }

    class login
    {
        public string passcode { get; set; }    
    }
}

3.login活动

Login.Click += async (object sender, EventArgs e) => {

    progress = ProgressDialog.Show (this, "", "Connecting...");

    var isLoginSuccessful = loginAuthenticator.AuthenticateUser                
    (password.Text, (value) => {
        Console.WriteLine (value);
    });//error

    if (progress != null) {
        progress.Dismiss ();
        progress = null;
    }

    if (isLoginSuccessful) {                
        StartActivity (typeof(Ledger_HomeActivity));
        this.Finish ();
    } else {
       Toast.MakeText (this, "Invalid Login credentials! try    again", ToastLength.Short).Show ();
    }
};

Answer 1

看起来function表示您使用true或false调用的回调方法，并且不返回任何值您。在这种情况下，您应该Action<bool>而不是Func<bool>，因为Func<bool>执行相反的操作 - 它不需要参数，并会向您返回bool值。

Answer 2

错误出现在此行

var isLoginSuccessful = loginAuthenticator.AuthenticateUser (password.Text, (value) => { Console.WriteLine (value); }):

Func<bool>返回一个布尔值而不期待任何东西。你想要的是Action<bool>，它需要一个布尔值但返回void：

public bool AuthenticateUser (string passcode, Action<bool> function)
{
    function(true);
}

委托`System.Func <bool>＆＃39;不需要`1＆＃39;参数

2 个答案: