Set selected value (SharePiont list lookup type) in AddForm

[Hotkomar]

Hello,

I'm a beginner. Last Friday I started creating my first powerApp.

It is easy inventory, that contain two Sharepoint list (Item inventory and activity logs). I started with default template from tutorial (BrowseScreen,EditScreen and DetailScreen).
On DetailScreen I display item detail from item inventory (Default settings) and below this detail I display gallery, that contains this item's activity logs. On Header this gallery I have icon for adding new activity log, that redirect to LogEditScreen. LogEditScreen contain Header and Edit form.

Here is begin of my problem. I would like to automaticly set item name instead of default generated dropdown menu, that allows selection of all saved item names. I searched everywhere and tried everything, but I can't resolve it.

My Idea is, that I transmit item name from DetailScreen to LogEditScreen (Ideally as hidden label) and user fills rest of form. So I make sure the item is selected correctly and user can't add activity log for other item.

Sharepoint Lists definition
item inventory: item name (string),Handed over from (date),Borrower(String),...
activity logs: activity name (string), note (string), item name (lookup item name from item inventory)

I will be extremely grateful for any advice or reference to a tutorial that would help me.

[v-siky-msft]

@Hotkomar 

1. Set the OnSelect property of gallery in BrowseScreen: 

Set(VarItemName, ThisItem.'item name') 

2. The Item name field in activity logs is a combo box in default, set the DefaultSelectedItems property:

LookUp(Choices('activity logs'.'item name'), Value=VarItemName)

3. Then the combo box will automatically select that item name, if you don't want user change it, just set the combo box mode to View, it will show as a label.

Sik