C# 从 LINQ 计算对象初始化期间的日期时间差异

Question

下面的代码运行良好，它从 SQL 表返回数据:

    List<TypeA> Class1 = ( from rec in Entity.Context.Table  select new Class1
                      { NAME = rec.name,
                        FIRSTDATE = rec.firstdate,
                        LASTDATE = rec.lastdate

                         //my func CalcTimeDiff, doesnt work
                          ElapsedMin = CalcTimeDiff(LASTDATE, FIRSTDATE) 

                       }).ToList();
public class Class1
{
   public string  NAME = {get; set;}
   public Nullable<DateTime> FIRSTDATE = {get; set;}
   public Nullable<DateTime> LASTDATE = {get; set;}
   public int ElapsedMin = {get; set;}

   // My function to calculate time difference
    public int CalcTimeDiff ( DateTime A, DateTime B)
          {
              TimeSpan Diff = A - B;
              int MinElapsed = (int)Diff.TotalMinutes;
              return MinElapsed;
            }
}

我正在寻找的是将计算 LASTDATE 和 FIRSTDATE 之间的 DateTime 差异的方法添加到 Class1 类，并在 Class1 初始化时调用它。但仍然没有运气，出现错误我不能使用非静态字段......知道如何管理它吗？

Answer 1

除非你需要 ElapsedMin 是可设置的(我不明白你为什么要这样做)，只需将它设为计算属性即可:

public int ElapsedMin => CalcTimeDiff(FirstDate, LastDate);

或

public int ElapsedMin => (int)(LastDate - FirstDate).Value.TotalMinutes;