Add display method in a listpage form - axapta

Question

I want to add a display method in the datasource of a listpage form. I can't add straightly because datasources come from an AOT query. How can I do it?
Thanks for help in advance.
The display method:
public display String255 UserNames()
{
DirPartyName partyName;
DirPersonUser personUser;
DirPerson person;
UserInfo userInfo;
String255 userList = "";
partyName = DirPersonUser::userId2Name(this.UserId);
if(partyName)
{
while select Name from person
exists join personUser
where personUser.PersonParty == person.RecId
&& personUser.User == this.UserId
{
userList += person.Name + ",";
}
}
if (!partyName)
{
while select Name from userInfo
where userInfo.Id == this.UserId
{
userList += userInfo.name + ",";
}
}
partyName = (select firstonly Name from userInfo where userInfo.Id == this.UserId).Name;
if (!partyName)
userList += this.UserId + ",";
strDel(userList,strLen(userList),1);
return userList;
}

Answer 1

I had a same requirement and we did it with a real physical field in the table TrvExpTable after the field is in the table we fill it on opening the list page.
In the init(), before the super(), of the form you can call that method:
public void updateTrvExpTableApprovers()
{
TrvExpTable trvExpTable;
TrvExpTrans trvExpTrans;
WorkflowWorkItemTable workflowItemTable;
String255 approversNames;
HcmWorker HcmWorker;
DirPersonUser dirPersonUser;
Name name;
ttsBegin;
while select forUpdate trvExpTable where trvExpTable.ApprovalStatus == TrvAppStatus::Pending
{
approversNames = "";
while select userId from workflowItemTable
where workflowItemTable.RefRecId == trvExpTable.RecId &&
workflowItemTable.RefTableId == trvExpTable.TableId &&
workflowItemTable.Status == WorkflowWorkItemStatus::Pending
{
select firstonly hcmWorker
join firstonly PersonParty, ValidFrom, ValidTo from dirPersonUser
where dirPersonUser.User == workflowItemTable.userId &&
hcmWorker.Person == dirPersonUser.PersonParty;
name = HcmWorker.name();
if (!name)
{
name = workflowItemTable.userId;
}
if(approversNames)
{
if (!strScan(approversNames, name, 0, 255))
{
approversNames += ', ' + name;
}
}
else
{
approversNames = name;
}
}
trvExpTable.ApproversNames = approversNames;
trvExpTable.update();
}
update_recordSet trvExpTable
setting ApproversNames = ""
where trvExpTable.ApprovalStatus != TrvAppStatus::Pending && trvExpTable.ApproversNames != "";
ttsCommit;
}
It is not the most efficient way but in our case it is working perfect for more than a year now.
Also that way the user could CTRL+G on that field in the grid, which is not a option using the display methods.
Best Regards,
Kristian

Answer 2

Why don't you try writing display method in table method as use same in list page? That is good option.
If you still want to write display method in form data-source level then change your display method like below.
public display String255 UserNames(DataSourcetablename _tableName)
{ ....
Use _tableName where ever you are using "this".
You can refer PurchEditLines form in standard Ax 2012 and see
display ImageRes backOrder(PurchParmLine _purchParmLine).
For more details on display method click here