项目之间的类持久化

Question

我知道我不应该问这个问题,但不管是什么,我都错过了让我疯了!我以前做了很多次,我只能把它放到老年和轻微的衰老.

我有一个类,有两个对象,在构造函数中初始化...

public class EbayFunctions
{
    private static ApiContext apiContext = null;
    private static List<StoreCategoriesFlattened> storeCategories =  new List<StoreCategoriesFlattened>();

    public EbayFunctions()
    {
        ApiContext apiContext = GetApiContext();
        List<StoreCategoriesFlattened> storeCategories = GetFlattenedStoreCategories();
    }
    public string GetStoreCategoryIdForItem(string category)
    {
       var result = storeCategories.Find(x => x.CCDatabaseMatch == category);
       return ""; //Ignore will return a value
    }
}

然后我有一个表单应用程序(测试工具),使用该类和按钮单击我调用方法...

namespace EbayTestHarness
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void cmdGetEbayStoreCatID_Click(object sender, EventArgs e)
        {
            EbayFunctions ebf = new EbayFunctions();
            string ddd = ebf.GetStoreCategoryIdForItem("Motors > Bikes");

        }
    }
}

但是,apiContext在调用之间storeCategories会持续存在但会被填充,EbayFunctions ebf = new EbayFunctions();并且在调用时string ddd = ebf.GetStoreCategoryIdForItem("Motors > Bikes");为null .

我知道它有些愚蠢,但我错过了什么？

Answer 1

你的问题在这里:

private static ApiContext apiContext = null;
private static List<StoreCategoriesFlattened> storeCategories =  new List<StoreCategoriesFlattened>();

public EbayFunctions()
{
    ApiContext apiContext = GetApiContext();  // local!!
    List<StoreCategoriesFlattened> storeCategories = GetFlattenedStoreCategories();  // local!!
}

你没有设置静态字段 - 你引入的局部变量然后超出范围并且(最终)被垃圾收集.取出类型指标来设置静态字段:

public EbayFunctions()
{
    apiContext = GetApiContext();
    storeCategories = GetFlattenedStoreCategories();
}

另外,正如@PatrickHofman指出的那样,静态成员的初始化应该进行一次 - 最好是在静态构造函数中:

static EbayFunctions()
{
    apiContext = GetApiContext();
    storeCategories = GetFlattenedStoreCategories();
}