零售标签打印应用：如何在DiscountService类引用PrintLabels的WeekNum变量？

问题背景 #

我们有一款简易零售标签打印应用，包含选择项表格与数量设置，涉及两个核心类：

• PrintLabels类：内部计算并使用表示当前年周数的WeekNum变量
• public类DiscountService：包含CurrentColorCode变量（共6种颜色，按周循环切换）

当前问题：当手动选择非循环规则的颜色后关闭应用，重新打开时会因dat文件已保存该自定义颜色，导致显示与当前周数不匹配的错误颜色。需要修改DiscountService类，通过引用WeekNum来初始化对应周数的起始颜色。

现有代码 #

DiscountService类代码 #

public int CurrentColorCode
{
    get
    {
        return currentColorCode;
    }
    set
    {
        // Ensure the color code is in range
        if (value < colorList.Count)
        {   
            scheduledColor = 
            currentColorCode = value;
        }
        else
        {
            currentColorCode = colorList.Count;
        }
    }
}

PrintLabels类代码 #

private void pd_PrintPage(object sender, PrintPageEventArgs e)
{
    DateTimeFormatInfo dfi = DateTimeFormatInfo.CurrentInfo;

    DateTime d = DateTime.Today;
    Calendar cal = dfi.Calendar;
    int WeekNum = cal.GetWeekOfYear(d, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
    if (WeekNum > 52)
    {
        DateTime newYear = d.AddDays(7);
        int newYearWeekNum = cal.GetWeekOfYear(newYear, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
        if (newYearWeekNum == 2)
        {
            WeekNum = 1;
        }
    }
    e.Graphics.DrawImage(generateBarcode(barcodeString),58, 50);
}

解决方案 #

1. 提取周数计算为公共可复用方法 #

将PrintLabels内的周数计算逻辑抽离为静态公共方法，方便DiscountService调用：

// 在PrintLabels类中添加静态方法
public static int GetCurrentWeekNum()
{
    DateTimeFormatInfo dfi = DateTimeFormatInfo.CurrentInfo;
    DateTime d = DateTime.Today;
    Calendar cal = dfi.Calendar;
    int weekNum = cal.GetWeekOfYear(d, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
    
    if (weekNum > 52)
    {
        DateTime newYear = d.AddDays(7);
        int newYearWeekNum = cal.GetWeekOfYear(newYear, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
        if (newYearWeekNum == 2)
        {
            weekNum = 1;
        }
    }
    
    return weekNum;
}

2. 修改DiscountService类添加周数初始化逻辑 #

在DiscountService的构造方法或初始化流程中，调用公共周数方法，通过取模计算对应周的初始颜色：

public class DiscountService
{
    private List<int> colorList; // 假设已定义的6种颜色列表
    private int currentColorCode;
    private int scheduledColor;

    public int CurrentColorCode
    {
        get => currentColorCode;
        set
        {
            if (value < colorList.Count)
            {
                scheduledColor = currentColorCode = value;
            }
            else
            {
                currentColorCode = colorList.Count;
            }
        }
    }

    // 构造时自动按周初始化颜色
    public DiscountService()
    {
        // 此处确保colorList已完成初始化（如colorList = new List<int> {0,1,2,3,4,5};）
        InitializeColorByWeek();
    }

    private void InitializeColorByWeek()
    {
        int weekNum = PrintLabels.GetCurrentWeekNum();
        // 按6种颜色循环，计算当前周对应的初始颜色代码
        int initialColor = (weekNum - 1) % colorList.Count;
        CurrentColorCode = initialColor;
    }

    // 公开初始化方法，用于应用重启加载dat文件后重置颜色
    public void ResetColorToWeekDefault()
    {
        InitializeColorByWeek();
    }
}

3. 应用重启时的处理逻辑 #

当应用重新启动并加载dat文件后，若检测到当前颜色不符合周循环规则，调用ResetColorToWeekDefault()方法，将颜色重置为当前周的默认值。

内容的提问来源于stack exchange，提问作者noobice94