Difference between [_THISROW].[_THIS] and [_THIS] in Form View

[jyothis_m]

I found this recently while filling a form in Appsheet. Thought of sharing it with the community.

[_THISROW].[_THIS] value of the current column current row (from table i.e. ghseet in my case)

[_THIS] value of the current column in the form-view

I shall describe the usage of both with a sample scenerio

Consider a table with 2 columns [Date] , [Shift]

Lets say we want to set the initial value of column [Shift] based on the value of column [Date]

For this I can use either of the two expressions given below

IF([_Thisrow].[Date]=TODAY(),"A","B")

IF([Date]=TODAY(),"A","B")

The first expression will consider the value of Date from Gsheet i.e. the saved data from Table

The second expression will consider the value of Date from the Form-View i.e. if i change the Date in the Form-View, the Shift updates instantly in the Form-View which does not happen in the case of first expression.

Hope this is useful.

[Fabian_Weller]

That's cool thank you @jyothis_m. I'm think many of us thought that [Column] and [_THISROW].[Column] would be exactly the same.

If I understand right, you are not talking about Add a new row, but about Edit an existing row, right? If so I think you have enabled "Reset on Edit" to force the initial value to recalculate, right?

Is [_THISROW].[Date] acting the same as [_THISROW_BEFORE].[Date]?

May you also share a usecase for that? I think that the initial value of column [Shift] will behalf different in Add and in Edit. How do you communicate this to the users so that they don't get confused?

[dbaum]

Re use case: Various community posts reference leveraging this distinction in Valid if expressions to prevent duplicate values across a column's rows--e.g., NOT(IN([_THIS], Table[Column] - [_THISROW].[Column])).

[jyothis_m]

Thank you @dbaum for pointing out this case 😊👍

[jyothis_m]

Thank you @Fabian_Weller 

I have checked both the cases i.e. ADD and EDIT please see the GIF below. 

ADD and EDIT ROW

[DATE] always updates and takes the live value from Form-View for both ADD and EDIT

[_THISROW].[DATE] as well as [_THISROW_BEFORE].[DATE] is behaving the same way and does not update unless the Form is saved for both ADD and EDIT

Hope this is what you were referring to  

[Fabian_Weller]

Thank you @jyothis_m for the GIF. Now I got it 😀
So [_THISROW].[Column] or [_THISROW_BEFORE].[Column] memorizes the Initial value in an add. Or the value in the sheet in an edit. That's quite interesting. I didn't expect that [_THISROW_BEFORE].[Column] would work in an add.

One usecase that comes to my mind: You can show the "before value" in the column description., or in a VC. You can show the before value only if the value has changed.
But in my testings this is working only with 
[_THISROW_BEFORE].[Column]
Not with
[_THISROW].[Column]
Nor with
[_THISROW].[_THIS] (gives the error "Unable to find column '_THIS'")

Here is the GIF

Show More

This is the expression I use in Column Description of column [Enum]:

"Enum"&
IF(
[_THISROW_BEFORE].[Enum]<>[Enum],
" (the before value was: "&[_THISROW_BEFORE].[Enum]&")",
""
)

[Koichi_Tsuji]

@jyothis_m 

Good catch! and thanks for sharing.

Did you test this with New Desktop UX ?  The same behaivior, did you observer with new desktop UX?

@takuya_miyai 

@Arthur_Rallu 

[jyothis_m]

Hi @Koichi_Tsuji I have tested it now in the New Desktop UX. There is some change seen here. Posting the screen recording of the same below

Screen Recording 

[Koichi_Tsuji]

@jyothis_m 

Thanks mate. This is useful.

@Arthur_Rallu 

@Adam-google 

Gentleman, this is better to look into.... in preparation for new desktop UX release.

@takuya_miyai 

[Koichi_Tsuji]

@jyothis_m 

Sorry for this question which is nothing to do with your topic.

Which and what GIF service are you using to capture the GIF you are shering here???

[jyothis_m]

I do the screen recording using ZD Soft Screen Recorder and then convert it to GIF online using EZGIF 

[Fabian_Weller]

I use Screen To Gif.

[Kawano164]

Great Tip! Thank you very much!

I find that if [_THISROW] is used in SHOW? expression it's calcurated not only when saved but also the other page is selected. So [_THISROW] probaly don't consider value from G sheet in SHOW? expression.

P.S.
I want more explanation in help page about [_THISROW]...