Question

我想生成一个以1000开头的用户ID，为每个用户递增一个（1000,1001,1002等）。种子随机语句的位置似乎都没有种子...（在构造函数或main中）。为什么我的随机语句没有在以下代码中正确初始化1000种子？

public class Student
{
    public string FullName { get; set; }
    public int StudentID { get; set; }

    //constructor to initialize FullName and StudentID
    public Student(string name, int ID)
    {
        FullName = name;
        Random rnd = new Random();
        StudentID = rnd.Next(1000, 1050); // creates a number greater than 1000
        return;
    }
    public override string ToString()
    {
        return string.Format("ID: {0}\n Name: {1}", StudentID, FullName);
    }
}

public class StudentTest
{
    static void Main(string[] args)
    {
        Student student1 = new Student("Amy Lee", 1000);
        Student student2 = new Student("John Williams", 1001);
        Console.WriteLine(student1);
        Console.WriteLine(student2);
        Console.WriteLine("\nPress any key to exit program");
        Console.ReadKey();
    }
}

Answer 1

Random生成随机数，而不是连续数。

声明int变量并为每个StudentID增加它。

public class Student
{
    public string FullName { get; set; }
    public int StudentID { get; set; }
    private static int _currentId = 1000;

    public Student(string name)
    {
        FullName = name;
        StudentID = _currentId++;
        return;
    }
    public override string ToString()
    {
        return string.Format("ID: {0}\n Name: {1}", StudentID, FullName);
    }
}

Answer 2

我想生成一个以1000开头的用户ID，为每个用户增加一个（1000,1001,1002等）。

然后你不应该尝试使用随机生成器，因为它将返回随机而不是序列号。

根据您的示例代码，您在哪里（1）不使用线程，（2）不使用数据库（3）而不保存创建的Student实例，实现您想要的最简单方法是以下内容：

public class Student
{
    private static int _curID = 1000;

    public static int GenerateNextID()
    {
        var id = _curID;
        _curID++;
        return id;
    }

    public string FullName { get; set; }
    public int StudentID { get; private set; }

    //constructor to initialize FullName and StudentID
    public Student(string name, int ID)
    {
        FullName = name;
        StudentID = ID;
    }
    public override string ToString()
    {
        return string.Format("ID: {0}\n Name: {1}", StudentID, FullName);
    }
}

并使用它：

public class StudentTest
{
    static void Main(string[] args)
    {
        Student student1 = new Student("Amy Lee", Student.GenerateNextID());
        Student student2 = new Student("John Williams", Student.GenerateNextID());
        Console.WriteLine(student1);
        Console.WriteLine(student2);
        Console.WriteLine("\nPress any key to exit program");
        Console.ReadKey();
    }
}

随机播种问题和可能的构造函数问题

2 个答案: