Executing Method Call - C#

Question

I'm just wondering if there is a better way of executing multiple methods depending on a value?

I have a Property that gets the NumberOflegs. NumberOfLegs can have a value between 1-6. If the value is 1, it needs to execute InsertLeg1Details. If the value is 2, it needs to execute InsertLeg1Details and InsertLeg2Details, etc.

  private void SaveLegs()
    {
        switch (NumberOfLegs)
        {
            case 1:
                SaveDataALC.SaveFlight(InsertLeg1Details());
                break;
            case 2:
                SaveDataALC.SaveFlight(InsertLeg1Details());
                SaveDataALC.SaveFlight(InsertLeg2Details());
                break;
            case 3:
                SaveDataALC.SaveFlight(InsertLeg1Details());
                SaveDataALC.SaveFlight(InsertLeg2Details());
                SaveDataALC.SaveFlight(InsertLeg3Details());
                break;
            case 4:
                SaveDataALC.SaveFlight(InsertLeg1Details());
                SaveDataALC.SaveFlight(InsertLeg2Details());
                SaveDataALC.SaveFlight(InsertLeg3Details());
                SaveDataALC.SaveFlight(InsertLeg4Details());
                break;
            case 5:
                SaveDataALC.SaveFlight(InsertLeg1Details());
                SaveDataALC.SaveFlight(InsertLeg2Details());
                SaveDataALC.SaveFlight(InsertLeg3Details());
                SaveDataALC.SaveFlight(InsertLeg4Details());
                SaveDataALC.SaveFlight(InsertLeg5Details());
                break;
            case 6:
                SaveDataALC.SaveFlight(InsertLeg1Details());
                SaveDataALC.SaveFlight(InsertLeg2Details());
                SaveDataALC.SaveFlight(InsertLeg3Details());
                SaveDataALC.SaveFlight(InsertLeg4Details());
                SaveDataALC.SaveFlight(InsertLeg5Details());
                SaveDataALC.SaveFlight(InsertLeg6Details());
                break;
        }
    }

Answer 1

With reflection you can do something like this

Type thisType = this.GetType();
for(int i = 1; i <= NumberOfLegs; i++)
{
  string toBeCalledMethodName = $"InsertLeg{i}Details";
  MethodInfo toBeCalledMethod = thisType.GetMethod(toBeCalledMethodName);

  var details = (FlightDetails)toBeCalledMethod.Invoke(this);
  SaveDataALC.SaveFlight(details);
}

I assumed your InsertLegXYZ methods are returning FlightDetails instances based on your previous question.

Answer 2

You should strive to avoid repeating operations like that.

My suggestion would be to test at each stage whether there's more work to do. If we've finished, then return.

private void SaveLegs()
{
    if (NumberOfLegs < 1 || NumberOfLegs > 6) { return; }

    SaveDataALC.SaveFlight(InsertLeg1Details());
    if (NumberOfLegs == 1) { return; }

    SaveDataALC.SaveFlight(InsertLeg2Details());
    if (NumberOfLegs == 2) { return; }

    SaveDataALC.SaveFlight(InsertLeg3Details());
    if (NumberOfLegs == 3) { return; }

    SaveDataALC.SaveFlight(InsertLeg4Details());
    if (NumberOfLegs == 4) { return; }

    SaveDataALC.SaveFlight(InsertLeg5Details());
    if (NumberOfLegs == 5) { return; }

    SaveDataALC.SaveFlight(InsertLeg6Details());
}

Assuming you have control over the functions, consider replacing (or augmenting) them with a single function that takes a leg number as argument - the code then becomes a simple loop:

private void SaveLegs()
{
    for (int i = 1;  i <= NumberOfLegs;  ++i) {
        SaveDataALC.SaveFlight(InsertLegDetails(i));
    }
}

Here, I've assumed that InsertLegDetails() will respond appropriately (e.g. throw an exception) if its argument is too high - the original action of just ignoring all the data seems a poor choice to me.

Answer 3

Why are there InsertLeg<N>Details()s in the first place?

Alternative assuming order of execution insignificant, not quite Duff's device:

switch (NumberOfLegs)
{
    case 6:
        SaveDataALC.SaveFlight(InsertLeg6Details());
        goto case 5;
    case 5:
        SaveDataALC.SaveFlight(InsertLeg5Details());
        goto case 4;
    case 4:
        SaveDataALC.SaveFlight(InsertLeg4Details());
        goto case 3;
    case 3:
        SaveDataALC.SaveFlight(InsertLeg3Details());
        goto case 2;
    case 2:
        SaveDataALC.SaveFlight(InsertLeg2Details());
        goto case 1;
    case 1:
        SaveDataALC.SaveFlight(InsertLeg1Details());
        break;
}