Reduce multiple foreach loops in code C#

Question

I have wrote a really messy code, just because I did not had an idea how to loop through the multiple list of objects.

Code is working what it suppose to do, but I am not confident with it. Does someone has an idea how this kind of code can be refactored so it is more readable?

foreach (var outlet in merchant.Outlets)
{
    if (outlet != null)
    {
        foreach (var terminal in merchant.Terminals)
        {
            if (terminal != null)
            {
                foreach (var agreement in terminal.AssociateAgreements)
                {
                    var bankInfo = new Bank();
                    if (agreement != null)
                    {
                        bankInfo.UniqueID = AgreementUniqueCode + agreement.ID;
                        bankInfo.BankBIC = agreement.BankAccountInformation.SwiftBIC;
                        bankInfo.BankName = agreement.BankAccountInformation.BankName;
                        bankInfo.Address =
                            AddressEntityToAddress(agreement.BankAccountInformation.BankAddress,
                                BankingType);

                        bankInfo.type = BankType;
                    }
                    banksAccountInformation.Add(bankInfo);
                }
            }
        }
    }
}

Use methods. You may add a method to Outlet such as ProcessTerminals, and one to Terminal such as ProcessAgreements. — Cecilio Pardo
– Cecilio Pardo, Commented May 13, 2016 at 9:16
You might want to put this question in 'Code Review' stackoverflow, not really appropriate here. — Stacker-flow
– Stacker-flow, Commented May 13, 2016 at 9:17
You could also remove the if conditions to match with NULL, because foreach loop always itreate on values in the collection and collection doesn't have the NULL insertions. — Shubhit304
– Shubhit304, Commented May 13, 2016 at 9:20
@Shubhit304: Foreach loops also process null values and collection may contain null values. Therfore the null check is correct. — JanDotNet
– JanDotNet, Commented May 13, 2016 at 9:39
@JNS: this happens only if the collection is of user defined datatype in which user manages the collection and fill it by values. Other wise I dont think .net will return you any collection having NULL values in between collections total count objects. — Shubhit304
– Shubhit304, Commented May 13, 2016 at 9:58

Tim Schmelter · Accepted Answer · 2016-05-13 09:19:05Z

4

You could use LINQ, especially SelectMany and Where:

List<Bank> banksAccountInformation = merchant
    .Where(m => m.Outlets != null && m.Terminals != null)
    .SelectMany(m => m.Terminals
        .SelectMany(t => t.AssociateAgreements
            .Where(aa => aa != null)
            .Select(aa => new Bank
            {
                UniqueID = AgreementUniqueCode + aa.ID
                // ...
            })))
    .ToList();

answered May 13, 2016 at 9:19

Tim Schmelter

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Comments

JanDotNet · Accepted Answer · 2016-05-13 09:33:40Z

3

You could also use the linq query syntax:

var outletQuery = from outlet in merchant.Outlets
                  where outlet != null
                  select outlet;

var agreementQuery = from terminal in merchant.Terminals
                     where terminal != null
                     from agreement in terminal.AssociateAgreements
                     select agreement;

foreach (var outlet in outletQuery)
{
    foreach (var agreement in agreementQuery)
    {
       ProcessAgreement(agreement);
    }
}

answered May 13, 2016 at 9:33

JanDotNet

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Comments

Pavel Voronin · Accepted Answer · 2016-05-13 09:19:27Z

3

If the only thing you want to is drilling down the object hierarchy, then you can use extension methods or linq:

// here you get a flattened collection of Terminals
merchants.SelectMany( m => m.Terminals)
// here you get a flattened collection of all AssociateAgreements of all Terminals
   .SelectMany( t => t.AssociateAgreements)

answered May 13, 2016 at 9:19

Pavel Voronin

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Comments

wonsik Lee · Accepted Answer · 2021-02-23 00:34:06Z

0

if i am:

foreach (var outlet in merchant.Outlets)
{
    if (outlet == null)
        continue;

    foreach (var terminal in merchant.Terminals)
    {
        if (terminal == null)
            continue;

        foreach (var agreement in terminal.AssociateAgreements)
        {
            if (agreement == null)
                continue;

            //TODO
        }
    }
}

answered Feb 23, 2021 at 0:34

wonsik Lee

1

1 Comment

Vimal Patel Over a year ago

Please explain the code as well while posting an answer.

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