Dropdown OnSelect and OnChange Actions not firing

powerapps
choba78 picture choba78 · Sep 14, 2016 · Viewed 8.4k times · Source

I added a textbox called TextBox1 to my PowerApps form.

Then in the OnSelect and OnChange Actions/Events I add the following code

TextBox1.Text="Hallo world"

When I run the app and change the select values in the dropdown then the textbox text does not change.

Why does the OnChange or OnSelect events not get triggered?

Answer

carlosfigueira picture carlosfigueira · Sep 14, 2016

The expression TextBox1.Text="Hallo world" doesn't mean an assignment in PowerApps as it does in many programming languages. Instead, it is a boolean expression, with no side effects (it will compare the text property of the text box with the string "Hallo world".

If you want to use variables, you need to use the UpdateContext function. In your case, you'd have something like this in the OnChange/OnSelect property of a control:

UpdateContext({ myVar: "Hallo world" })

And set the Text property of the TextBox1 to myVar.

This doc has more information on the use of variables in PowerApps.

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