Code Snippet: Rolling Paged Navigation Control
Coldfusion, UIAn approach to rolling links to "pages" in a result set when you want to constrain the amount of space used for navigation. The basic idea is having a leading and trailing offset relative to the page of results you're on to produce something that looks like this:
Page 1: Previous 1 2 3 4 5 Next
Page 2: Previous 1 2 3 4 5 Next
Page 3: Previous 1 2 3 4 5 Next
Page 4: Previous 2 3 4 5 6 Next
Page 5: Previous 3 4 5 6 7 Next
Page 6: Previous 4 5 6 7 8 Next
Page 7: Previous 5 6 7 8 9 Next
Page 8: Previous 6 7 8 9 10 Next
Page 9: Previous 6 7 8 9 10 Next
Page 10: Previous 6 7 8 9 10 Next
Where the underlined values would hyperlinks in practice. Presumably you would pass the value for what page is being viewed along the URL or via a form POST.
Code:
<cffunction name="pagination" output="false" returntype="struct" hint=" Keys: start int end int hasPrev bool hasNext bool "> <cfargument name="cPage" type="numeric" required="true"/> <cfargument name="pages" type="numeric" required="true"/> <cfargument name="startOffset" type="numeric" required="true"/> <cfargument name="endOffset" type="numeric" required="true"/> <cfset var local = structNew()/> <cfset var p = structNew()> <cfset var window = min(pages, startOffset + endOffset + 1)> <cfif cPage LT 1 OR cPage GT pages> <cfthrow message="cPage (#cPage#) must be a value between 1 and #pages#."> </cfif> <cfset p.end = min(pages, max(cPage + endOffset, window))> <cfset p.start = max(0, min(cPage - startOffset, p.end - window )) + 1> <cfset p.hasPrev = p.start GT 1> <cfset p.hasNext = p.end LT pages> <cfreturn p> </cffunction> <cffunction name="showNav" output="false" access="public" returntype="string" hint=""> <cfargument name="p" type="struct" required="true"/> <cfargument name="cPage" type="numeric" required="true"/> <cfset var local = structNew()/> <cfset local.output = arrayNew(1)> <cfif p.hasPrev> <cfset arrayAppend(local.output, "<u>Previous</u>")> <cfelse> <cfset arrayAppend(local.output, "Previous")> </cfif> <cfloop from="#p.start#" to="#p.end#" index="local.idx"> <cfif local.idx EQ cPage> <cfset arrayAppend(local.output, local.idx)> <cfelse> <cfset arrayAppend(local.output, "<u>#local.idx#</u>")> </cfif> </cfloop> <cfif p.hasNext> <cfset arrayAppend(local.output, "<u>Next</u>")> <cfelse> <cfset arrayAppend(local.output, "Next")> </cfif> <cfreturn arrayToList(local.output, " ")> </cffunction> <cfset pages = 10> <cfset startOffset = 2> <cfset endOffset = 2> <cfoutput> <pre> <cfloop from="1" to="#pages#" index="page">Page #page#: #showNav(pagination(cPage=page,pages=pages,startOffset=startOffset,endOffset=endOffset), page)# </cfloop> </pre> </cfoutput>
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