比较数据网格视图列和列

Question

I'm stuck on one part whereby I have no idea how to solve it. Basically, I have one table, "Shifthours" and another one which is "employeeshift". Shifthours table have shift_Start and shift_Stop. employeeshift table have StartTime and EndTime. I'm comparing shift_Start and StartTime. I have linked this 2 tables together using foreign key and the question I asked is that I want the shift_Start to compare with the StartTime and shift_Stop to compare with the EndTime and see the employee fit which shift and the shift_Start and shift_Stop will appear at the column that the employee is eligible.

Currently I got a code that only joins 2 table together but not comparing the timings.

private void LoadAllEmpShift()
    {
        using (testEntities Setupctx = new testEntities())
        {
            BindingSource BS = new BindingSource();
            var Viewemp = from ES in Setupctx.employeeshifts
                          join shifthour sh in Setupctx.shifthours on ES.ShiftHourID equals sh.idShiftHours
                         select new
                         {
                             ES.EmployeeShiftID,
                             ShiftHour_Start = sh.shiftTiming_start,
                             ShiftHour_Stop = sh.shiftTiming_stop,
                             ES.EmployeeName,
                             ES.StartTime,
                             ES.EndTime,
                             ES.Date
                         };


            BS.DataSource = Viewemp;
            dgvShift.DataSource = BS;
        }
    }

Anyone knows how to do this?

Answer 1

Edit:

You said you were trying to find where the employee hours match with a set of shift times. It would be nice to have some sample data and the algorithm that you want to use to determine what is a good shift time match.

I have assumed here that the best way to do that is to base the employee's start time off the nearest shift start time.

In the following code, I use the let function to essentially look through the shift hours and find the set of shift hours that are nearest to the employee's start time.

var Viewemp = from ES in Setupctx.employeeshifts
      join sh in Setupctx.shifthours on ES.ShiftHourID equals sh.idShiftHours 
         into shifts
      let diff = shifts
          .OrderBy (s => 
                    // this is the line that needs attention:
                    System.Math.Abs((int)(ES.StartTime - s.shiftTiming_start))
                   )
                   .First ()
      select new
      {
          ES.EmployeeShiftID,
          ShiftHour_Start = diff.shiftTiming_start,
          ShiftHour_Stop = diff.shiftTiming_stop,
          ES.EmployeeName,
          ES.StartTime,
          ES.EndTime,
          ES.Date
      };

Update

My type in database for the StartTime and EndTime is string instead of time

In the above code the important logic is finding the absolute value difference between ES.StartTime and s.shiftTiming_start and the smallest difference indicates the best match for shift hour. Unfortunately, your database stores this data as a string and you need to compare them as numeric.

Linq-to-Entities does not contain an easy way to convert string to int function.

I think your next step would be to look into how you can convert those string values to int values. Take a look at this question as I think it might help you out:

Convert String to Int in EF 4.0