Reset a variable value

[Anonymous]

Hello all,

I have a brief question regarding variables. I have in one screen a button that uses the value ID of the item, coded as:

Set(idSSTVar, ThisItem.'ID Orden')

What I want to know is how to, when I backtrack to a superior level or different screen, to put that value as blank/"".

[wyotim]

One way I accomplish this is to use the OnHidden propery on the screen I am navigating away from. To reset the value, I am pretty sure it depends on what the variable's type is (text, number, etc.). If you are using text, you can use:

Set(idSSTVar, "")

If it is a number, this can be a bit tricky, depending on the values. For IDs, I set it to 0. For actual values, you may have to get creative to set it to something that can be recognized as a default value. If you have meaningful zeros, 0 wouldn't work too well. At any rate, the code would look like this:

Set(idSSTVar, 0)

Let me know if that helps or not!

[Anonymous]

@wyotim 

The 'OnHidden' property is of the screen itself? What does it mean? Like, when it is not seen by the user? And is it better that, or when the user selects the backtrack icon ( "<" ) to have it 'on select' instead?

[R3dKap · Accepted solution]

Hi @Anonymous,

If you want to reset the value of a global variable when you hit a BACK button you can just put the following code in the OnSelect event of the BACK button:

Set(idSSTVar, Blank())

If you want to reset the value of the variable when you change screens, as @wyotim suggested, you can just put the same code in the OnHidden event of the screen when the variable is set to the ID value.

Is that what you wanted to achieve ?

Emmanuel

[wyotim · Accepted solution]

Each screen has an OnHidden property, just like the OnVisible or Fill, BackgroundImage, etc. Basically what happens with the OnHidden is as soon as that screen is navigated away from, it executes whatever code is in that property. The OnVisible property is similar only it executes code when the screen is navigated to.

You could definitely put all of that in the OnSelect property of the back icon. You would probably want to put it before whatever code navigates away, so if you are using the Back property it would look like:

Set(idSSTVar, 0);
Back(ScreenTransition.None)

Please note that I used a single semicolon to break the code, which is the US version. If you are outside the US, you may need to use a double semicolon like so:

Set(idSSTVar, 0);; 
Back(ScreenTransition.None)

Let me know if that sorts it out for you.

*edit for missed words!*

[wyotim]

@R3dKap, good call on Blank(). That is the better way to go for sure. My use of "" and 0 is an old Excel habit that is still hanging on apparently!

[Anonymous]

@wyotim @R3dKap 

Thank you both for your answers, this works for what I needed (:

[wyotim]

Happy to help out!

[R3dKap]

Gald we could help...