Simple Intro to CFC
Filed under CFC , ColdFusion
Recently, my ColdFusion User Group had an introduction to CFC's lesson. I found it difficult to understand some simple concepts. When I'm learning things, I have to start on the simplest level and work my way up, so thats my reason for this blog in a nut shell.
I set up a very small database with 1 table ( tblTest ), 2 columns ( tstFirstName, tstLasName ) and filled it with some test data.
My goal was to have a simple input form asking for someones last name, then return the user with the first name by calling a cfc.
Here is my cfc:
<cfcomponent>
<cffunction name="ReturnFirstName" access="public" returntype="string" hint="This will return the first name when passed a last name">
<cfargument name="LastName" type="string" required="Yes">
<CFQUERY name="get_employees_first_name" datasource="dsnTest">
select tstFirstName
from tblTest
where tstLastName = '#arguments.LastName#'
</CFQUERY>
<CFRETURN get_employees_first_name.tstFirstName>
</cffunction>
</cfcomponent>
Here is my cfm:
<CFINVOKE component="myCFC" method="ReturnFirstName" returnvariable="foo">
<cfif ISDEFINED('form.btnSubmit')>
<CFINVOKEARGUMENT name="LastName" value="#Form.myinput#">
<cfelse>
<CFINVOKEARGUMENT name="LastName" value="">
</cfif>
</CFINVOKE>
<body>
<cfform name="form1" action="cfcTest.cfm" preservedata="yes">
<br/>
Hello <CFOUTPUT>#foo#</CFOUTPUT>
<br />
What is your Last Name?
<cfinput type="text" name="myinput">
<br/>
<cfinput type="submit" name="btnSubmit">
</cfform>
</body>
This very simplified version a cfc makes it very easy to see what is actually happening and how it can be useful. Now that I have created this cfc, I can send the persons last name to the cfc throughout my entire application and it will easily send me back the persons first name. I never have to write that function again.
Here is a great tutorial that helped me understand this simple, but extremely useful function: http://tutorial80.easycfm.com/
Jul10