Question

我想创建一个应用程序，显示当前打开的商店。每个商店都有名称，工作时间和类别。我制作了一个包含每个商店及其属性的列表，但是当我使用foreach方法时它不会显示任何一个......你碰巧知道问题是什么吗？或者以不同的方式解决它？

 class Shop
 {
    public string name;
    public DayOfWeek day{ get; set; }
    public TimeSpan start{ get; set; }
    public TimeSpan end{ get; set; }
    public string address{ get; set; }
    public string category{ get; set; }




    public Shop(string name, DayOfWeek day, TimeSpan start, TimeSpan end, string address, string category)
        {
        name = this.name;
        day = this.day;
        start = this.start;
        end = this.end;
        address = this.address;
        category = this.category;
        }
    }


    public openshops()
    {
        List<Shop> openShop = new List<Shop>();
        openShop.Add(new Shop("ill forno", DayOfWeek.Tuesday, new TimeSpan(18, 0, 0), new TimeSpan(00, 0, 0), "ermoupoli", "pizza"));
        openShop.Add(new Shop("Η ΣΥΡΑ", DayOfWeek.Sunday, new TimeSpan(12, 0, 0), new TimeSpan(00, 0, 0), "ermoupoli", "pizza"));
        openShop.Add(new Shop("ΠΙΤΑΚΙ", DayOfWeek.Tuesday, new TimeSpan(19, 30, 0), new TimeSpan(00, 30, 0), "ermoupoli", "souvlaki"));

        this.InitializeComponent();


        DayOfWeek today = DateTime.Today.DayOfWeek;
        TimeSpan now = DateTime.Now.TimeOfDay;
        if (today == DayOfWeek.Friday)
        {
            foreach (Shop shop in openShop)
            {
                if ((now > shop.start) && (now < shop.end))
                {
                    Button btn = new Button();
                    btn.Content = shop.name;
                    myStackPanel.Children.Add(btn);
                }

            }
        }
    }

Answer 1

您正在反转构造函数中的设置逻辑：

你应该设置这样的成员：

public Shop(string name, DayOfWeek day, TimeSpan start, TimeSpan end, string address, string category)
    {
    this.name = name;
    this.day = day;
    this.start = start;
    this.end = end;
    this.address = address;
    this.category = category;
    }

Answer 2

public Shop(string name, DayOfWeek day, TimeSpan start, TimeSpan end, string address, string category)
    {
    name = this.name;
    day = this.day;
    start = this.start;
    end = this.end;
    address = this.address;
    category = this.category;
    }
}

您正在为类中的未实例化变量设置参数值...

关键字

此

用于引用当前对象实例。

此外，按照惯例，属性名称应为Pascal大小写，因此如果您将代码重新格式化为：

class Shop
{
//public string name; //This one should have getters and setters too, fields shouldn't be exposed.
public string Name { get; set; }
public DayOfWeek Day{ get; set; }
public TimeSpan Start{ get; set; }
public TimeSpan End{ get; set; }
public string Address{ get; set; }
public string Category{ get; set; }




public Shop(string name, DayOfWeek day, TimeSpan start, TimeSpan end, string address, string category)
    {
    this.Name = name;
    this.Day = day;
    this.Start = start;
    this.End = end;
    this.Address = address;
    this.Category = category;
    }
}

一切都应该没问题。

关于惯例的参考： https://msdn.microsoft.com/en-us/library/vstudio/ms229043%28v=vs.100%29.aspx

有关公开类字段的参考： http://thatextramile.be/blog/2009/10/slutty-types/

Answer 3

除了修复设置属性的方式外，还有开始和结束时间的问题。

openShop.Add(new Shop("ill forno", DayOfWeek.Tuesday, new TimeSpan(18, 0, 0), new TimeSpan(00, 0, 0), "ermoupoli", "pizza"));
openShop.Add(new Shop("Η ΣΥΡΑ", DayOfWeek.Sunday, new TimeSpan(12, 0, 0), new TimeSpan(00, 0, 0), "ermoupoli", "pizza"));
openShop.Add(new Shop("ΠΙΤΑΚΙ", DayOfWeek.Tuesday, new TimeSpan(19, 30, 0), new TimeSpan(00, 30, 0), "ermoupoli", "souvlaki"));

这些Shop个对象的开始时间大于结束时间，因此if语句

if ((now > shop.start) && (now < shop.end))

对于这些Shop对象，始终为false。我猜你真的想交换那些价值。

openShop.Add(new Shop("ill forno", DayOfWeek.Tuesday, new TimeSpan(00, 0, 0), new TimeSpan(18, 0, 0), "ermoupoli", "pizza"));
openShop.Add(new Shop("Η ΣΥΡΑ", DayOfWeek.Sunday, new TimeSpan(00, 0, 0), new TimeSpan(12, 0, 0), "ermoupoli", "pizza"));
openShop.Add(new Shop("ΠΙΤΑΚΙ", DayOfWeek.Tuesday, new TimeSpan(00, 30, 0), new TimeSpan(19, 30, 0), "ermoupoli", "souvlaki"));

列表不会显示内容

3 个答案: