Coding Considerations

Curly Brackets

Curly brackets indicate that a parameter or parameters are optional. Take the CNSImage_Version function for example:

CNSImage_Version{( Option )}

This function can be called without any parameters because the parameter section is surrounded by curly brackets indicating that is it optional. Using the function in this manner looks like:

CNSImage_Version

The above code would return the version number of the plug-in. However, if you would like to get an Auto Update friendly version number, you can specify "Auto Update" for the "Option" parameter:

CNSImage_Version( "Auto Update" )

In more complex functions, there may be multiple optional parameters. Note that if there are optional parameters before one that you need to use, you must include any parameters before it. Consider the CNSImage_Import function:

CNSImage_Import{( Path {; TypeList {; Prompt }} )}

If you want to specify the "Prompt" parameter, you must also specify the two optional parameters before it. Following is an incorrect example and a correct example:

INCORRECT: CNSImage_Import( "JPEG;PNG" ; "Please choose an image" )
CORRECT: CNSImage_Import( "" ; "JPEG;PNG" ; "Please choose an image" ))

FileMaker Version Considerations

When plug-ins were first introduced, the only place you really wanted to use a plug-in function was the Set Field script step. However, since FileMaker 4, many new advancements have taken place. Though the Set Field script step is still a very common place to use plug-in functions, there are now many places that can logically be used. For a list of a few of these places, see the next section titled "Places to use CNS Image Functions".

It is important to keep in mind what versions of FileMaker will be in use when using CNS Image and other plug-ins. For example, creating a variable using the Set Variable script step can be very convenient, however, that functionality only exists in FileMaker 8 and greater. If you or your users use FileMaker 7, then your script calls would fall on deaf ears if you used Set Variable script step. In addition, when using functions in a variable you will be less likely to see the results returned from the plug-in (such as error messages), because a variable cannot but put on a layout like a field.

Places to use CNS Image Functions

You can use CNS Image functions in any calculation engine dialog in FileMaker. Keep in mind that just because you can do something does not mean it is actually useful.

There are several places that fit very well depending on the situation:

Calculation field
Auto-Enter Calculated value
Validation by calculation
Set Field Script/Button step
Insert Calculated Result Script/Button step
Show Custom Dialog
Set Variable Script/Button Step
Custom Functions
and more...

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Coding Considerations

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