Issue to add/ remove item to collection with button

[Xinlin]

Hi all, 

I have a Checkbox gallery that is automatically set to all checked if a certain value of dropdown is selected. However, whenever I try to uncheck items and add to the collection, the checkbox checked all the items and add to the gallery. I couldn't uncheck item that I don't need from the gallery. Here are the logic that I set for my buttons, checkbox and gallery. 

Checkbox property:

Default  = If(DataCardValue1.Selected.Value = 'TableDropdownName''.Yes, true,false)
OnCheck = Collect(Collection,ThisItem)
OnUncheck = Remove(Collection,ThisItem)

I also have a Clear button and Add to Collection button that let users to uncheck the checkbox before adding to collection. 

Clear button: 

If(DataCardValue11.Selected.Value = 'TableDropdownName'.Yes Or DataCardValue1.Selected.Value = 'TableDropdownName'.No, true, false) 

Add to Collection button: 

UpdateContext({varResetCheckbox:true});
    UpdateContext({varResetCheckbox:false});
ForAll(Filter(Gallery.AllItems,Checkbox1.Value = true),
Collect(Collection,ThisRecord))

[poweractivate]

@Xinlin 

Try one of two things, with #2 being more preferable if it works

1. Try to add All to the end of  the Remove

Checkbox property:

OnUncheck = Remove(Collection,ThisItem, All)

2. Try to change Collect to Patch below - and keep the OnUncheck as Remove like you had before:

Checkbox property:

OnCheck = Patch(Collection,ThisItem)
OnUncheck = Remove(Collection,ThisItem)

See if it helps @Xinlin 

[Xinlin]

Hi @poweractivate, thanks for helping out. I've tried both of the solutions but unfortunately it doesn't seem to work. 

I guess the reason that causing the problem would be the Default of my checkbox. Now I'm trying to add a new button that perhaps to allow to click and "Select all" items in the checkbox gallery but didn't manage to do it. The logic I'm tried is this: 

Collect(Collection, ForAll(Gallery.AllItems,ThisRecord))

[poweractivate]

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@Xinlin wrote:

Default  = If(DataCardValue1.Selected.Value = 'TableDropdownName''.Yes, true,false)

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@Xinlin In the above, I don't think the formula is even checking the Collection at all, so you are right this could be the issue. Maybe try something like this instead:

If(!IsBlank(LookUp(Collection,ItemName = DataCardValue1.Selected.Value)),true,false)

 In the above, replace ItemName and DataCardValue1.Selected.Value with something else that makes sense for you if needed.

See if it helps further @Xinlin