VBA中Enum内续行符多行注释报错，其他场景可用的原因

Great question—this inconsistency is one of those quirky VBA parser behaviors that catches even experienced developers off guard. Let’s break it down:

First, the official rule (that’s being bent in one case) #

VBA’s documentation explicitly states that line continuation characters (_) are for splitting executable code lines only, not comments. Comments (started with ') are meant to be self-contained on a single line. That said, the parser treats different code blocks differently, which leads to the behavior you’re seeing.

Why Enum blocks throw an error #

Enum is a strict, specialized module-level structure designed solely to define sets of named constants. The VBA parser checks every line inside an Enum block against a very narrow set of valid syntax: either an enumeration entry (e.g., Red = 1) or a single-line comment.

When you use a line continuation with a comment inside an Enum, the parser doesn’t recognize the combined lines as a valid comment. Instead, it interprets the continuation as an attempt to split an executable Enum entry—and the second line (the continued comment) doesn’t fit the Enum’s syntax rules. Hence the "Invalid inside Enum" error.

Why Subs/Functions let it slide #

Subroutine and function blocks are far more flexible. The parser expects a mix of executable code, variable declarations, comments, and even empty lines. When you use a line continuation with a comment here, the parser is lenient: it treats the continuation and the following comment as non-executable, ignored content. It doesn’t enforce the same strict syntax checks as it does for Enum blocks, since procedures are meant to accommodate varied code structures.

A quick note on best practices #

Even though Subs/Functions tolerate line-continued comments, this is a parser quirk, not a supported feature. It’s still better to stick to single-line comments to avoid potential compatibility issues across different Office versions or future VBA updates.

内容的提问来源于stack exchange，提问作者QHarr