Not sure why this isn't working.
If the content of Gallery 'Unique ID' field equals any entry in UnqID field of MemberList set button to DisplayMode.Disabled else Edit.
If(NewMemberGalleryUniqueIDFld.Text = MemberCollection.UnqID,true, Disabled,Edit)
I suspect you are trying to compare different data types, hence the redlined '=' operator.
If MemberCollection.UnqID data type is a number then try wrapping your NewMemberGalleryUniqueIDFld in the Value() function, ie
Unfortunately, I cannot see your data types, it's up to you to share those.
So, back to the original question,
1. Are you adding this code onto the DisplyMode of the button?
2. Are you checking NewMemberGalleryUniqueIDFld.Text against a single value (because this is what I assumed your condition was doing based on the code you supplied) ... OR ... is it being checked against a LIST OF ITEMS to see if it existing in that list. If the latter, then there is more to do with your code than a simple comparison check.
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