Unselect behavior in listbox

[AmitLoh-Powerap]

How do I achieve unselect behavior in listbox(I do see uncheck in checkbox but not in listbox)

I have seen alternative workaround of using checkbox which is not useful because on scroll it does retain checkbox values.

I need listbox unselect.

[v-micsh-msft]

Hi @AmitLoh-Powerap,

Is this a similar question to the following?

https://powerusers.microsoft.com/t5/PowerApps-Forum/how-to-autom-select-all-values-of-listbox-on-loa...

If not, then you may consider to submit another idea to have the listbox control add the Unselecteditems property.

Regards

[CarlosFigueira]

As you noticed, there is no "OnSelected/OnUnselected" actions for the list box. Please consider creating a new entry in the PowerApps Ideas page for that.

For now, you can know when items have been added or removed, but you will need to maintain the state of the list, and use the OnChange action to determine which items have been added or removed. Let's go to an example step-by-step:

For example, the app below has a list box with some items:

The items in this app are hardcoded, but they could have come from any data source:

ListBox1.Items: Table(
    {Id:1, Name:"Scooby Doo", Age:7, Human:false},
    {Id:2, Name:"Shaggy Rogers", Age:17, Human:true},
    {Id:3, Name:"Fred Jones", Age:17, Human:true},
    {Id:4, Name:"Daphne Blake", Age:16, Human:true},
    {Id:5, Name:"Velma Dinkley", Age:15, Human:true})

We need to know the first state - for which I have the Initialize button. In a real app it would probably be done on the screen's OnVisible action:

Button1.OnSelect: ClearCollect(selected, ListBox1.SelectedItems.Id); Clear(added); Clear(removed)

Now every time we get an OnChange action in the list, we can compare the items with the stored selected items, and update the added/removed collections:

ListBox1.OnChange: ClearCollect(added, Filter(ListBox1.SelectedItems.Id, !(Id in selected)));
    ClearCollect(removed, Filter(selected, !(Id in ListBox1.SelectedItems.Id)));
    ClearCollect(selected, ListBox1.SelectedItems.Id)

Whenever the list selection changes, then we'll add to the "added" collection the ids of all items that are selected but were not previously selected; likewise, we'll add to the "removed" collection the ids of the items that were previously selected but are not selected in the list. At the end, we update the "selected" collection to reflect the new contents of the list.

The formulas in the textboxes in the app are shown below. Notice that if you want to take an action when an item is selected / unselected, then you would likely do that on the same ListBox's OnChange expression.

Textbox formulas:

TextBox1.Text: "Listbox selected: " & Concat(ListBox1.SelectedItems, Id & ",")
TextBox2.Text: "Added: " & Concat(added, Id & ",")
TextBox3.Text: "Removed: " & Concat(removed, Id & ",")
TextBox4.Text: "Selected: " & Concat(selected, Id & ",")

Hope this helps!

[AmitLoh-Powerap]

Thanks!

How do unselect all items or coupl of items programatically on clear button click, is it possible to write refresh page?

[CarlosFigueira · Accepted solution]

If you set the Default property of the listbox to an empty value, you will clear the selected items. Notice that you may need to change the value for the data flow to propagate its value - if it was empty before, and you set it to empty again, it won't be propagated.

So in the list, you would set the following property:

Default: myVar

And on the button to unselect all items:

OnSelect: UpdateContext({ myVar: "1" }); UpdateContext({ myVar: "" })

[Nachtschicht]

@AmitLoh-Powerap  ... 6 years later, no changes so far but this may or must change in the future.

I use a button with the following select action which is quite popular:

UpdateContext({ListReset: !ListReset})

The variable ListReset resides in Listbox.Data.Default, toggling it removes the focus from the selected list item(s), similar to the proposal of @CarlosFigueira but saving some key strokes, just setting it to false does not work ...