Extension of Class in D365 for Operations

We can create extension for class but can use/call only Public Members/Methods. Private and Protected can not be accessed from Extension Class.

Added new field TstField in MainAccount Table using extension.
Would like to show newly added field on Trail balance Form/Report.
Added new field TstField in LedgerTrialBalanceTmp Table using extension.

/// <summary>

/// Extension Class for LedgerTrialBalanceDP

/// </summary>
[ExtensionOf(classStr(LedgerTrialBalanceDP))]

final class HNWLedgerTrialBalanceDP_Extension

{

    protected void new()

    {

    }

    /// <summary>

    /// Updating new field in <c>LedgerTrialBalanceTmp</c> Table

    /// </summary>

    public void UpdateTstField()

    {

        MainAccount                         mainAccount;

        DimensionAttributeValueCombination  ledgerDimension;

        LedgerTrialBalanceTmp               ledgerTrialBalanceTmp;

       

        ledgerTrialBalanceTmp = this.getLedgerTrialBalanceTmp();     

        update_recordset ledgerTrialBalanceTmp

            setting
            TstField     =   mainAccount.TstField
            join mainAccount
        exists join ledgerDimension where
            ledgerDimension.MainAccount == mainAccount.RecId &&
            ledgerDimension.RecId == ledgerTrialBalanceTmp.LedgerDimension;

        this.setTrialBalanceTmpTable(ledgerTrialBalanceTmp);

    }

}

Create postEventHandler for processReport method in LedgerTrialBalanceDP Class
and call our newly created method in Extension Class of LedgerTrialBalanceDP

public class HNWLedgerTrailBalanceHandlersExt
{

    [PostHandlerFor(classStr(LedgerTrialBalanceDP), methodStr(LedgerTrialBalanceDP, processReport))]

    public static void LedgerTrialBalanceDP_Post_processReport(XppPrePostArgs args)        {

       LedgerTrialBalanceDP ledgerTrialBalanceDP = args.getThis();
        ledgerTrialBalanceDP.UpdateTstField();
     }
}