你调用的对象是空的

Question

I have the following code -

private static void convert()
    {
        string csv = File.ReadAllText("test.csv");
        XDocument doc = ConvertCsvToXML(csv, new[] { "," });
        doc.Save("update.xml");

        XmlTextReader reader = new XmlTextReader("update.xml");
        XmlDocument testDoc = new XmlDocument();
        testDoc.Load(@"update.xml");

        XDocument turnip = XDocument.Load("update.xml");
        webservice.function[] test = new webservice.function[1];
        webservice.function CallWebService = new webservice.function();

        foreach(XElement el in turnip.Descendants("row"))
        {
                            test[0].com = System.Convert.ToInt32(el.Descendants("var").Where(x => (string)x.Attribute("name") == "com").SingleOrDefault().Attribute("value").Value);
            test[0].Centre = el.Descendants("var").Where(x => (string)x.Attribute("name") == "Centre").SingleOrDefault().Attribute("value").Value;
            test[0].CCentre = el.Descendants("var").Where(x => (string)x.Attribute("name") == "CCentre").SingleOrDefault().Attribute("value").Value;

            MessageBox.Show(test[0].person, "person");
            MessageBox.Show(System.Convert.ToString(test[0].actually), "Actually");
            MessageBox.Show(System.Convert.ToString(test[0].com), "Com");

            CallWebService.updateFeedStatus(test);
        }

It is coming up with the error of - NullReferenceException was unhandled, saying that the object reference not set to an instance of an object. The error occurs on the first line test[0].account.

How can I get past this?

Answer 1

Initializing an array does not initialize the objects in the array. Try adding the second line below (assuming you want to use the default constructor):

webservice.singleSummary[] test = new webservice.singleSummary[1];
test[0] = new webservice.singleSummary();

Answer 2

1. Put a debugger on the process.
2. Identify which line of code is generating the error. (Assuming Visual Studio)
3. Test the object references on that line one by one until you determine which one has the null reference.
4. Put in a null check before the line to fix the problem.

Answer 3

我猜你的xml有一个你需要在你的xname中包含所需元素的命名空间，但正如其他评论所提到的，没有完全公开就没有什么可以做的。