c# - 不能在同一类内的函数中使用变量声明类。为什么 ？

Question

我已经在类“Main”中声明了一个名为“context2”的变量。但是我不能在函数“Main_Load”中使用变量。我做错了什么？

using System;
using System.Windows.Forms;
using Soapi;
using Soapi.Domain;

namespace SO_Console_Client
{
    public partial class Main : Form
    {
        const string apiKey = "*************";
        var context2 = new ApiContext(apiKey).Initialize(false);
        public Main(String GravatarURL, User user)
        {
            InitializeComponent();
            pictureBox1.Load(GravatarURL);  //Loads the Gravatar image from the url

            //set the reputation details
            lblRep.Text = String.Format("Reputation: {0}", user.Reputation);

            //Sets the badge details
            lblBadge.Text = String.Format("Badges: gold={0} silver={1} bronze={2}", user.BadgeCounts.Gold, user.BadgeCounts.Silver, user.BadgeCounts.Bronze);

            groupBox1.Text = user.DisplayName.ToString();
        }

        private void Main_Load(object sender, EventArgs e)
        {
            Soapi.Queries.QuestionsUnansweredQuery query = context2.Official.StackOverflow.Questions.Unanswered;
            foreach (Question q in query)
            {
                try
                {
                    Console.WriteLine(q.Title.ToString());
                    //Console.WriteLine(q.Body.ToString());
                }
                catch (System.NullReferenceException ex)
                {

                }

            }

        }
    }
}

Answer 1

隐式类型不适用于字段；它仅适用于局部变量。

我认为这就是您的真实意图:

ApiContext context2 = new ApiContext(apiKey);

public Main(String GravatarURL, User user)
{
   context2.Initialize(false);
   ...
}

在极不可能的情况下，ApiContext 是某种流畅的接口(interface)，ApiContext.Initialize(bool) 返回一个不同的ApiContext对象，这应该是你想要的:

ApiContext context2 = new ApiContext(apiKey).Initialize(false); 

虽然如果你这样做会更清楚:

ApiContext context2;

public Main(String GravatarURL, User user)
{
   context2 = new ApiContext(apiKey).Initialize(false);
   ...
}

不过，我真的很怀疑。