MACROMEDIA COLDFUSION 4.5-CFML LANGUAGE Manuel d'utilisateur télécharger pdf (Page 42)

42 CHAPTER 30 Extending ColdFusion with CFX

Listing 30.8 (continued)

<br>

Standard Deviation:

<strong>#NumberFormat(MerchStats.StandardDeviation, “,0.00”)#</strong>

<br>

</cfoutput>

</body>

</html>

An Important Warning

If this all sounds too good to be true, it is—kind of. This whole strategy will fail if there is there is

already a variable called

FilmsStats in the calling ColdFusion page and that variable is anything

other than a structure. In such a case, ColdFusion will crash if a C++ CFX attempts to reference the

variable as a structure. With a Java CFX, the program won’t crash, but the tag will still throw an

error. To protect yourself against such a possibility, you could use a line like one of the following,

just before calling the CFX tag each time.

This line simply deletes the

FilmsStats variable if it exists already (if it doesn’t exist, nothing hap-

pens, so this line does no harm):

Alternatively, this line creates a new, empty FilmsStats structure (regardless of whether it already

exists):

Figure 30.12

CFX tags can

return multifaceted

information to

ColdFusion.

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MACROMEDIA COLDFUSION 4.5-CFML LANGUAGE Manuel d'utilisateur Page 42