ByRef Argument type mismatch with Boolean

Q: Which Access VBA pattern ranks just above this one at #61?

The pattern one rank above is “VS 2012.3 Referencing MS Access COM DLL, could not resolve COM reference error”. If your use case overlaps, compare both before committing.

The Problem (Q-score 2, ranked #62nd of 67 in the Access VBA archive)

The scenario as originally posted in 2014

I have some vba code in an Access form which produces a “ByRef Argument type mismatch” error when called under the following circumstances.

I have a small function

NullAndHide(ctl as control,displayitem as Boolean)

which works as expected when I call it like so.

Call NullAndHide(Me.Control,True)

However, if I use the following case statement to try to set the value of displayitem based on another control:

Dim PerPersonOption, PerRoomOption As Boolean

    Select Case PriceType_ID
Case Is = 1 'Per Person
    PerPersonOption = True
    PerRoomOption = False
Case Is = 2 'Per Room
    PerPersonOption = False
    PerRoomOption = True
End Select

And then

Call NullAndHide(Me.Control,PerPersonOption) I get the error:

ByRef Argument type mismatch

I’ve tested the the value of PerPersonOption with

msgBox PerPersonOption

and it returns the correct boolean value.

My function expects a Boolean, I’m giving it a Boolean – So why am I getting this error?

Why community consensus is tight on this one

Across 67 Access VBA entries in the archive, the accepted answer here holds solid answer (above median) status — meaning voters are unusually aligned on the right fix.

The Verified Solution — solid answer (above median) (+9)

Advisory answer — community consensus with reference links

Note: the verified answer below is a reference / advisory response rather than a copy-ready snippet.

When declaring Dim PerPersonOption, PerRoomOption As Boolean only PerRoomOption is type of Boolean, but PerPersonOption is Variant.

Try to use Dim PerPersonOption As Boolean, PerRoomOption As Boolean

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When to Use It — classic (2013–2016)

Ranked #62nd in its category — specialized fit

This pattern sits in the 71% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the Access VBA archive for a higher-consensus alternative.

What changed between 2014 and 2026

The answer is 12 years old. The Access VBA object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.

help
Frequently Asked Questions

Is this above-median answer still worth copying?
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Answer score +9 vs the Access VBA archive median ~4; this entry is solid. The score plus 2 supporting upvotes on the question itself (+2) means the asker and 8 subsequent voters all validated the approach.

This answer links out — what are the reference links worth following?
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Read the first external link for the canonical reference, then search this archive for a top-10 entry in the same category — advisory answers are best paired with a ranked code snippet to close the loop.

Published around 2014 — what’s changed since?
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Published 2014, which is 12 year(s) before today’s Office 2026 build. The Access VBA object model has had no breaking changes in that window. Three things to re-test: (1) blocked macros on downloaded files (Mark-of-the-Web), (2) 64-bit API declarations (PtrSafe, LongPtr), (3) any shift toward Office Scripts for web scenarios.

Which Access VBA pattern ranks just above this one at #61?
expand_more

The pattern one rank above is “VS 2012.3 Referencing MS Access COM DLL, could not resolve COM reference error”. If your use case overlaps, compare both before committing.

Data source: Community-verified Q&A snapshot. Q-score 2, Answer-score 9, original post 2014, ranked #62nd of 67 in the Access VBA archive. Last regenerated April 14, 2026.