Validations (no fun!)

Yeah, I know they aren’t fun, but enduring a little aggravation and extra work now will very likely save much more frustration later, so put on your big-boy (or girl) boots and tighten your belt.

What do we need to validate?

Is the given paragraph valid?

A Paragraph is an object in Word VBA which might not be assigned to anything in the document yet. If we tried to use it as such, the function would crash and pop up a mean message.

Fortunately, we’ve dealt with this situation several times before when working with ranges. Essentially, we check whether the wParagraph variable is Nothing (meaning it has yet to be assigned to a meaningful paragraph in the document). We use the “Is” operator (like a plus + sign for numbers but for VBA objects) to compare whether two objects are the same or whether one object Is currently Nothing.

This results in a Boolean value (True or False), so we can put it in a conditional statement. We can’t do anything if the paragraph variable isn’t assigned to a document paragraph, so we just exit the function.

Since the command is so simple, I like the more compact notation on one line.

What about the styles?

Styles are an awkward subject since VBA doesn’t give us tools to validate whether a style exists in the current document (well, not without being cumbersome and painfully slow). To rectify this, we can create our own. A previous article covered a function IsStyle to do just this.

We “pass” the function a plain text style name or one stored in a String variable as shown here. The function returns a True value if the style exists in the document or the current template (usually Normat.dot) or False if not.

Style validations with IsStyle

We only want to exit the function if the style does not exist, so we include a Not “operator” with each style check. Remember a Not switches True and False values. Our two given styles from the function parameters are StyleA and StyleDefault.

Our second style check is:

If either style doesn’t exist, we need to exit the subroutine, or the style assignment later would crash the function along with whatever macro was calling it. The Or operator gives us a True result if either condition is True, so we combine the two conditions.

On a personal note, I avoided style validations for a long time, but I my style macros often crashed when I switched between documents. Now, they run more smoothly.

Combined style validation

We exit the function if this compound condition is True. The concise version is:

We could combine both validations (the paragraph and styles) into one conditional statement, but it looks a little messy, so I’m leaving them separated.

Changing a paragraph style

A Paragraph in VBA is an object with its own properties (data) and methods (actions). The style of the given paragraph wParagraph is easily accessed by referencing its Style property:

This technically refers to a Style Variant type, meaning in this case that it can refer to a Style object, a Style identifier, or a plain text name. The latter allows us to assign the style name directly to it.

StyleA is a plain text String variable, but VBA handles the details of actually applying the paragraph style in the background.

Style toggle

The toggle logic is straight forward, but you might squint a little bit as you read the description of it.

If the current paragraph style is already StyleDefault, then change it to StyleA. Otherwise change any other style to StyleDefault. A hybrid VBA-English conditional statement for this decision looks like:

Getting more VBA-ish, we check the paragraph style against StyleDefault. The condition is:

Technically, the left-hand side could refer to a Style object, a numeric identifier, or a plain text variable. VBA will decide which one by context based on the type of StyleDefault. Since StyleDefault is a String, it compares them as plain text. Does the plain text name of wParagraph.Style exactly match the String variable name?

The conditional statement is:

See this previous article if you would like a brief introduction the conditional statements in VBA.

Cycle variation

With the cycle between three styles, we essentially add a similar ElseIf condition in the middle to switch from StyleA to StyleB. The conditional statement is something like:

Converting this conceptual conditional statement to a VBA version for this function is:

Assign return value

We need to tell the user what style we changed the paragraph to be, so we set the function name to wParagraph’s Style property:

VBA will automatically interpret the Style property to be a plain text name because the function returns a String value.