将自定义类实例化为数组元素时出现问题 [英] Problem instantiating custom class as array element

问题描述

I've been working on an app to manage my iTunes collection, and have run into a bit of a snag. I've created two classes:

Column – Describes a column of information in the iTunes database
Track – Contains an array of Columns

When I instantiate a new Track object and attempt to build the array of Columns, each "new Column" statement overwrites the value of the previous array element.

I'm sure I'm missing something obvious – any ideas?

// this statement...
Track t = new Track();
// produces this output:
// array element 0 = Name
// array element 0 = Artist
// array element 1 = Artist

// Begin Column class
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TestBed
{
    public class Column
    {
        private static string _name;
        private static string _datatype = "string";
        private static Int16 _length = 0;
        public string Name
        {
            get { return _name; }
            set { _name = value; }
        }
        public string DataType
        {
            get { return _datatype; }
            set { _datatype = value; }
        }
        public Int16 Length
        {
            get { return _length; }
            set { _length = value; }
        }
        public Column(string name, string datatype, Int16 length)
        {

            _name = name;
            _datatype = datatype;

            if (datatype == "string" && length > 0)
            {_length = length; }
            else
            {_length = 0;}
        }

    }
}
// Begin Track class
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TestBed
{
    public class Track
    {
        private static Column[] _trackcolumns = new Column[2];
        public static Column[] TrackColumns
        {
            get {return _trackcolumns;}
            set { _trackcolumns = value; }
        }
        public Track()
        {

            _trackcolumns[0] = new Column("Name", "string", 30);
            Console.WriteLine("array element 0 = {0}",_trackcolumns[0].Name);

            _trackcolumns[1] = new Column("Artist", "string", 30);
            Console.WriteLine("array element 0 = {0}", _trackcolumns[0].Name);
            Console.WriteLine("array element 1 = {0}", _trackcolumns[1].Name);

        }
    }

推荐答案

static成员变量，为什么哦，上帝告诉我为什么?

问候，

Manfred

static member variables, why oh Lord tell me why?

Regards,

Manfred

这将解释为什么您的静态变量给您带来问题:

已解密的静态关键字 [

This will explain why your static variables are giving you problems:

Static Keyword Demystified[^]

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