Table Level Event Handler in d365 fo x++

[DataEventHandler(tableStr(PurchAgreementHeader), DataEventType::ModifiedField)]
public static void PurchAgreementHeader_onModifiedField(Common sender, DataEventArgs e)
{
ModifyFieldEventArgs    event = e as DataEventArgs;
PurchAgreementHeader    purchAgreementHeader = sender as PurchAgreementHeader;
FieldId                 fieldId = event.parmFieldId();
date                    emptyDate;
switch(fieldId)
{
case fieldNum(PurchAgreementHeader, BankGuarantee):
if(purchAgreementHeader.BankGuarantee == NoYes::No)
{
purchAgreementHeader.BankGuaranteeExpirationDate = emptyDate ;
purchAgreementHeader.BankGuaranteeNumber         = “”;
purchAgreementHeader.Bank                        = “”;
}
break;

}
}

 OnInserting - This method will be called during insertion of the record on the table.

[DataEventHandler(tableStr(HcmWorker), DataEventType::Inserting)]
public static void HcmWorker_onInserting(Common sender, DataEventArgs e)
{
    HcmWorker worker = sender as HcmWorker;
    //assign field values
}

OnUpdating - This method will be called during the updated of record on the table.

[DataEventHandler(tableStr(HcmWorker), DataEventType::Updating)]
public static void HcmWorker_onUpdating(Common sender, DataEventArgs e)
{
    HcmWorker worker = sender as HcmWorker;
    //assign field values
}

OnValidatingWrite - This event handler will be called when save button is clicked on the form to validate records and during insertion of record into a table.

[DataEventHandler(tableStr(HcmWorker), DataEventType::ValidatingWrite)]
public static void HcmWorker_onValidatingWrite(Common sender, DataEventArgs e)
{
    HcmWorker worker = sender as HcmWorker;
    ValidateEventArgs event = e as ValidateEventArgs;
    boolean ret = event.parmValidateResult();
    if(ret)
    {
        ret = checkFailed("Error");
        event.parmValidateResult(ret);
               
    }
}

OnValidatingField - This event handler will be called while validating values entered on the field in the form.

[DataEventHandler(tableStr(HcmWorker), DataEventType::ValidatingField)]
public static void HcmWorker_onValidatingField(Common sender, DataEventArgs e)
{
    HcmWorker worker = sender as HcmWorker;
    ValidateFieldEventArgs event = e as ValidateFieldEventArgs;
    boolean ret =event.parmValidateResult();
    if(ret)
    {
        switch(event.parmFieldId())
        {
            case fieldNum(HcmWorker, PersonnelNumber):
            ret = checkFailed("Error");
            break;
        }
    }
        event.parmValidateResult(ret);
}

OnModififyingField - This event handler will be called while some values are entered on the field in the form.

[DataEventHandler(tableStr(HcmWorker), DataEventType::ModifyingField)]
public static void HcmWorker_onModifyingField(Common sender, DataEventArgs e)
{
    HcmWorker worker = sender as HcmWorker;
    ModifyFieldEventArgs event = e as ModifyFieldEventArgs;
    switch(event.parmFieldId())
    {
        case fieldNum(HcmWorker, PersonnelNumber):
        //assign field values.
        break;
    }
}