Referencing Values in Collections

[StevePenner]

In the use of collections, I am finding the ability to reference values in them very unintuitive.

Even with the intellisense formula bar showing "Table" or "Record" or other primitive to complex data type, I came up with what I wanted only by ultimately stumbling upon it after several hours (!).

In one screen, a button was used with following OnSelect formula:

UpdateContext({MeetingDate: MeetingDatePicker.SelectedDate});
ClearCollect(AgendaCreate, {MeetingDate: MeetingDate, AgendaItems: 'CAB Agenda Admin'.'Level 1 Header'});
Navigate(EditAgendaItems,ScreenTransition.Fade)

In an image below, the collection shows a property (column?) "MeetingDate" with datetime value and a property "AgendaItems" shows a table, which is expanded to show a single column of rows of text.

In the next screen, these two properties (columns?) are utilized, the date converted to text and concatenated to
text in a text label, 

"Meeting Date: " & Text(First(AgendaCreate.MeetingDate).MeetingDate, DateTimeFormat.ShortDate)

and the single column table of text used to form the options in a scrollable list box.

First(AgendaCreate.AgendaItems).AgendaItems

The image of the screen and selected controls with their formula are indicated.

I have a feeling I am doing this wrong, because the patterns

First(AgendaCreate.MeetingDate).MeetingDate
First(AgendaCreate.AgendaItems).AgendaItems

are confusing. This states that AgendaCreate.MeetingDate is of type 'Table' when it seems not to be, and that it nonetheless returns a value of type 'Record' where we get the field 'MeetingDate'.

AgendaItems is clearly a property of collection AgendaCreate, and is intuitively a table, but First() returns a record that is a table. Seemingly a table within a table, which is not the case.

Why doesn't AgendaCreate.MeetingDate simply return the datetime value and AgendaCreate.AgendaItems.(columnName?) return the rows of text to be used as Items?  That seems intuitive to me.

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[v-bofeng-msft · Accepted solution]

Hi @StevePenner :

It looks like you have already got the value you want.

Do you just want to know why you should use 

First(AgendaCreate.MeetingDate).MeetingDate

instead of

AgendaCreate.MeetingDate

?

The point is  the value of AgendaCreate.MeetingDate is a list of datetime value.If you need to get a specific MeetingDates, you need to specify which record it comes from.So you can use 

First(AgendaCreate).MeetingDate

or

First(AgendaCreate.MeetingDate).MeetingDate

to get the MeetingDate in the first record in the table AgendaCreate.

Then,let‘s go back to the agendaitems field.

AgendaCreate.AgendaItems is a list of tables.So the value of 

First(AgendaCreate.AgendaItems).AgendaItems

or

First(AgendaCreate).AgendaItems

is a table in AgendaItems field in the first record of the table AgendaCreate .So it can be used as items property of the list box control.If you want to display it in a label control,you can try this :

Add a label control and set it's Text property to:

Concat(First(AgendaCreate).AgendaItems,Title,Char(13))

Best Regards,

Bof