成本管理系统是什么？从 0 到 1 理解核心逻辑与业务价值（附基础框架解析）

// 成本实体类定义示例
public class CostItem
{
    public int Id { get; set; }
    public string CostCode { get; set; }
    public string Description { get; set; }
    public decimal Amount { get; set; }
    public DateTime OccurrenceDate { get; set; }
    public int DepartmentId { get; set; }
    public int CostCategoryId { get; set; }
    
    // 导航属性
    public virtual Department Department { get; set; }
    public virtual CostCategory CostCategory { get; set; }
}

// 成本分类实体
public class CostCategory
{
    public int Id { get; set; }
    public string CategoryName { get; set; }
    public string Description { get; set; }
    
    // 导航属性
    public virtual ICollection CostItems { get; set; }
}

// 成本数据服务类示例
public class CostService : ICostService
{
    private readonly CostDbContext _context;
    
    public CostService(CostDbContext context)
    {
        _context = context;
    }
    
    // 获取部门成本汇总
    public async Task<>> GetDepartmentCostSummaryAsync(DateTime startDate, DateTime endDate)
    {
        return await _context.CostItems
            .Where(ci => ci.OccurrenceDate >= startDate && ci.OccurrenceDate <= endDate)
            .GroupBy(ci => ci.Department.DepartmentName)
            .Select(g => new { Department = g.Key, TotalCost = g.Sum(ci => ci.Amount) })
            .ToDictionaryAsync(x => x.Department, x => x.TotalCost);
    }
    
    // 添加成本记录
    public async Task AddCostItemAsync(CostItem costItem)
    {
        _context.CostItems.Add(costItem);
        await _context.SaveChangesAsync();
    }
}