这个名字不是“；t存在于当前上下文错误中

public static void ammount()
{
    foreach (mp3players value in mps)
    {
        Console.WriteLine("ID: " + value.id);
        Console.WriteLine("Model: " + value.model);
        Console.WriteLine();
    }
}

该代码具有CCD_ 3的知识。

您可以在方法中添加一个参数，使public static void ammount()看起来像public static void ammount(mp3players[] mps)。将修复此错误，但会导致另一个

您必须将mps传递到该方法中。

mps是mp3()方法中的局部变量。它不是全局变量，因此在ammount()方法中不可访问。

我明白你的意思了，你得到了编译错误The name 'mps' does not exist in the current context。因此，要解决此问题，必须将mps设置为全局变量，并在mp3()方法中设置该值，并在其他方法中使用该值。

结构mp3players｛

        private int ID;
        private string Make;
        private string Model;
        private int MBSize;
        private double Price;
        private int vr;
        public int id
        {
            get { return this.ID; }
            set { this.ID = value; }
        }
        public string make
        {
            get { return this.Make; }
            set { this.Make = value; }
        }
        public string model
        {
            get { return this.Model; }
            set { this.Model = value; }
        }
        public int mbsize
        {
            get { return this.MBSize; }
            set { this.MBSize = value; }
        }
        public double price
        {
            get { return this.Price; }
            set { this.Price = value; }
        }
        public int VR
        {
            get { return this.vr; }
            set { this.vr = value; }
        }
    }
    private static ArrayList  mps;
    public static void mp3()
    {
        mp3players mp1 = new mp3players();
        mp1.id = 1;
        mp1.make = "GET technologies .inc";
        mp1.model = "HF 410 ";
        mp1.mbsize = 4096;
        mp1.price = 129.95;
        mp1.VR = 500;
        mp3players mp2 = new mp3players();
        mp2.id = 2;
        mp2.make = "Far & Loud";
        mp2.model = "XM 600 ";
        mp2.mbsize = 8192;
        mp2.price = 224.95;
        mp2.VR = 500;
        mp3players mp3 = new mp3players();
        mp3.id = 3;
        mp3.make = "Innotivative";
        mp3.model = "Z3 ";
        mp3.mbsize = 512;
        mp3.price = 79.95;
        mp3.VR = 500;
        mp3players mp4 = new mp3players();
        mp4.id = 4;
        mp4.make = "Resistance S.A.";
        mp4.model = "3001 ";
        mp4.mbsize = 4096;
        mp4.price = 124.95;
        mp4.VR = 500;
        mp3players mp5 = new mp3players();
        mp5.id = 5;
        mp5.make = "CBA";
        mp5.model = "NXT volume ";
        mp5.mbsize = 2048;
        mp5.price = 159.05;
        mp5.VR = 500;
        mps = new ArrayList();
        mps.Add(mp1);
        mps.Add(mp2);
        mps.Add(mp3);
        mps.Add(mp4);
        mps.Add(mp5);
        foreach (mp3players value in mps)
        {
            Console.WriteLine("ID: " + value.id);
            Console.WriteLine("Make: " + value.make);
            Console.WriteLine("Model: " + value.model);
            Console.WriteLine("MBSize: " + value.mbsize);
            Console.WriteLine("Price: " + value.price);
            Console.WriteLine();
        }
    }
    public static void ammount()
    {
        foreach (mp3players value in mps)
        {
            Console.WriteLine("ID: " + value.id);
            Console.WriteLine("Model: " + value.model);
            Console.WriteLine();
        }
    }

函数public static void mp3()内部声明的变量"mps"，并且您正试图从另一个函数public static void ammount()访问该变量，但由于作用域的原因，这是不可行的。

要访问"mps"，您必须从mp3()函数中删除声明，并将其直接移动到您定义的类中：

public class MySongColl
{
   private static ArrayList mps = new ArrayList();
    struct mp3players
    {
       ....
       .... 
    }
    public static void mp3()
    {
        ....
        ....
    }
    public static void ammount()
    {
        ....
        ....
    }
}

注意：编写代码时请使用正确的命名约定。例如：函数名称ammunt（）中的拼写错误应该是amount（）。在声明结构mp3players等名称时使用camel-case。这些对于构建代码来说不是必需的，但对于开发人员来说是必不可少的