Question

I am working on some reporting code and I have found myself repeating a certain piece of code which contains a where and select cause over and over again? The only piece of information changing is the target field.

    private static void UpdateResultsListInstructions(List<ManagementInfo> managementInfo, KeyValuePair<int, int> item)
    {
        managementInfo
            .Where(m => m.YearMonthNo == item.Key)
            .Select(m => m.VolumeOfInstructionsReceivedInMonth = item.Value)
            .ToList();
    }

    private static void UpdateResultsListClaims(List<ManagementInfo> managementInfo, KeyValuePair<int, int> item)
    {
        managementInfo
            .Where(m => m.YearMonthNo == item.Key)
            .Select(m => m.VolumeOfClaimsCancelled = item.Value)
            .ToList();
    }

Is it possible to pass in the selector as an argument so I can reuse one method?

Along the lines of

UpdateCommonResultsList(managementInfo, item, (m => m.VolumeOfClaimsCancelled = item.Value))

I can probably rejig all the code so that this is not necessary but now that I’ve had the thought I’d like to see if its possible. Any help appreciated.

Answer 1

Although I don’t like the use of Select to update a list – I misread the question because it’s not usual to do that! – you can do it as follows:

private static void UpdateCommonResultsList(
    List<ManagementInfo> managementInfo,
    KeyValuePair<int, int> item,
    Action<ManagementInfo, int> action)
{
    managementInfo
        .Where(m => m.YearMonthNo == item.Key)
        .Select(m => { action(m, item.Value); return item.Value; })
        .ToList();
}

Call as

UpdateCommonResultsList(
    managementInfo,
    item,
    (m, i) => m.VolumeOfClaimsCancelled = i);

Your code will be a lot more conventional if you do this as

private static void UpdateCommonResultsList(
    List<ManagementInfo> managementInfo,
    KeyValuePair<int, int> item,
    Action<ManagementInfo, int> action)
{
    foreach (ManagementInfo m in managementInfo
        .Where(m => m.YearMonthNo == item.Key))
    {
        action(m, item.Value);
    }
}