从当前日期获取过去一年内修改的记录

Question

我有一个结果集，其结构如下。

List<BudgtedData> budgetData;
public class BudgtedData
{
    public decimal BudgetedCpmDataId { get; set; }
    public int ForecastYear { get; set; }
    public int ForecastMonth { get; set; }
}

我想获得去年的记录。 例如，如果我在2015年3月运行代码，则应该将2014年3月返回到2015年2月。如何在linq中实现此目标

Answer 1

我认为这段代码应该适合您：

int currentYear = DateTime.Now.Year; int currentMonth = DateTime.Now.Month;

var result = budgetData.Where(
       b => (b.ForecastYea.Equals(currentYear - 1)  
             && b.ForecastMonth >= currentMonth )
             ||(b.ForecastYear.Equals(currentYear)                       
             && b.ForecastMonth <= currentMonth - 1))
             .ToList();

Answer 2

这是解决方案：

var res = budgetData.Where(r => ((r.ForecastYear == (DateTime.Today.Year - 1) && r.ForecastMonth >= DateTime.Today.Month) || (r.ForecastYear == DateTime.Today.Year && r.ForecastMonth < DateTime.Today.Month))).ToList();

说明：如果年份是一年[在2015年是2014年]，请从“当前月份”开始选择数据。 否则，如果年份为当前年份，请从本月之前的月份中选择数据。

一个有效的例子：

 List<BudgtedData> budgetData = new List<BudgtedData>();
 budgetData.Add(new BudgtedData() { BudgetedCpmDataId = 1, ForecastMonth = 12, ForecastYear = 2014 });
 budgetData.Add(new BudgtedData() { BudgetedCpmDataId = 1, ForecastMonth = 1, ForecastYear = 2014 });
 budgetData.Add(new BudgtedData() { BudgetedCpmDataId = 1, ForecastMonth = 1, ForecastYear = 2013 });
 budgetData.Add(new BudgtedData() { BudgetedCpmDataId = 2, ForecastMonth = 2, ForecastYear = 2014 });
 budgetData.Add(new BudgtedData() { BudgetedCpmDataId = 2, ForecastMonth = 1, ForecastYear = 2015 });


 var res = budgetData.Where(r => ((r.ForecastYear == (DateTime.Today.Year - 1) && r.ForecastMonth >= DateTime.Today.Month) || (r.ForecastYear == DateTime.Today.Year && r.ForecastMonth < DateTime.Today.Month))).ToList();

 foreach (BudgtedData item in res)
 {
     Console.WriteLine(item.ForecastYear + "  "+ item.ForecastMonth);
 }

输出：

 2014 12
 2014 2
 2015 1