How to make a text box required when defining actions?

[Vishal2]

So, i am using a farily simple single page form in powerapps. What i want to do is something like this.

if,

DataCardValue12.Selected.Value = "Food"

When defining actions,

I want to make another specific mandatory. i.e. when datacardvalue12 is set to Food. Datacard Allergen is required(Mandatory)

What i have tried is add a rule. See screenshot.

Thanks heaps in advance 🙂

[RobEitzen · Accepted solution]

Create a variable and set the default value to false (field is not required) when the app starts, the screen is visible, or when a button is clicked.  Set the data card Allergen's Required property to your variable.  In the OnChange event for DataCardValue12's textbox to test the text and set the variable appropriately.

For example:

Button - Navigates to edit form's screen OnSelect: 

UpdateContext({varRequireAllergen: false})

Text Input Box - DataCardValue12.OnChange: 

UpdateContext({varRequireAllergen: If(DataCardValue12.Text="Food", true, false)})

Allergen_DataCard - Required property:

varRequireAllergen

The PowerApps default error handling for a required field will take over from there.

[Vishal2]

Hey Rob,

Thank-you for your response.

I managed to follow through to your instructions but seems to have hit a barrier.

I changed the approach very slightly since i am using a choice type and not a text box.

In the onSelect of the choice I have:

UpdateContext({varRequireAllergen: false})

in the onChange of the choice I have:

UpdateContext({varRequireAllergen: If(DataCardValue12.Selected.Value = "Food", true, false)})

And in the datacard that is supposed to turn mandatory after selecting food, I have 

varRequireAllergen

I have noticed that the data card does turn mandatory for a partial second as soon as i change the choice to Food, and changes it back. Your help is really appreciated mate. Thank-you

[Vishal2]

I managed to fix it using,

UpdateContext({varRequireAllergen: If(DataCardValue12.Selected.Value = "Food", true, false)}) in the onchange and removing everything else.

thank-you for your help.