公开课 - "is inaccessible due to its protection level. Only public types can be processed."

Question

我正在做一个测试项目来了解对象的XML序列化，我遇到了一个奇怪的运行时错误：

namespace SerializeTest
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }
    private void Form1_Load(object sender, EventArgs e)
    {
    }

    private void serializeConnection(Conn connection)
    {
        XmlSerializer serializer = new XmlSerializer(typeof(Conn));
        TextWriter textWriter = new StreamWriter(@"serialized.xml");
        serializer.Serialize(textWriter, connection);
        textWriter.Close();
    }
    static List<Conn> deserializeConnection()
    {
        XmlSerializer deserializer = new XmlSerializer(typeof(List<Conn>));
        TextReader textReader = new StreamReader(@"serialized.xml");
        List<Conn> connectionList;
        connectionList = (List<Conn>)deserializer.Deserialize(textReader);
        textReader.Close();
        return connectionList;
    }
    private void btnSerialize_Click(object sender, EventArgs e)
    {
        Conn conn = getConnection();
        serializeConnection(conn);
    }
    private Conn getConnection()
    {
        Conn connection = new Conn();
        connection.connectionName = txtName.Text;
        connection.address = txtAddress.Text;
        connection.height = 2542;
        connection.width = 4254;
        connection.password = txtPassword.Text;
        connection.smartSizing = false;
        connection.username = txtUsername.Text;
        connection.port = 474;
        return connection;
    }
    private void btnDeserialize_Click(object sender, EventArgs e)
    {
        int count = deserializeConnection().Count;
        lblStatus.Text = "Count: " + count;
    }
}
class Conn
{
    public Conn()
    {
    }
    public string connectionName { get; set; }
    public int height { get; set; }
    public int width { get; set; }
    public string address { get; set; }
    public string username { get; set; }
    public string password { get; set; }
    public int port { get; set; }
    public bool smartSizing { get; set; }
}
}

该类是公共的 - 我不明白可能导致此错误的原因。任何帮助将不胜感激。

Answer 1

该类是公共的

不，不是。以下是声明：

class Conn
{
    ...
}

您尚未指定任何访问修饰符，因此它默认为 internal（假设它是非嵌套的）。仅仅因为它有一个公共构造函数并不能使其公开。您需要明确公开它：

public class Conn
{
    ...
}