Coldfusion and Pagination

问题:

First I am very new to ColdFusion, but am learning pretty quickly. So I am trying to build a large database that originally displays all results with 25 lines per page and have a next/prev link to navigate through the pages.

That all works fine, but when I perform a search, and when the new results display of about a couple of pages worth, the pagination links don't work. When I click on the "next" link it goes back to the original all records display. How can I fix this or what do I need to do to make it work?

Sorry I'm new at posting and this is my first one. Hope this is better.

My pagination code...

<cfset Next = StartRow + DisplayRows>
<cfset Previous = StartRow - DisplayRows> 

<cfoutput> 
  <cfif Previous GTE 1> 
    <a href="#CGI.Script_Name#?StartRow=#Previous#"><b>Previous #DisplayRows# Records</b></a> 
  <cfelse> 
    Previous Records 
  </cfif> 
  <b> | </b> 
  <cfif Next lte records.RecordCount> 
    <a href="#CGI.Script_Name#?StartRow=#Next#"><b>Next 
    <cfif (records.RecordCount - Next) lt DisplayRows> 
      #Evalute((records.RecordCount - Next)+1)# 
    <cfelse> 
      #DisplayRows# 
    </cfif>Records</b></a>
  <cfelse> Next Records 
  </cfif> 
<cfoutput>

My code at the top...

<cfparam name="StartRow" default="1"> 
<cfparam name="DisplayRows" default="25"> 

<cfset ToRow = StartRow + (DisplayRows - 1)> 
<cfif ToRow gt records.RecordCount> 
  <cfset ToRow = records.RecordCount> 
</cfif>

Let me know if you need to see more...thank you.

回答1:

Here is an example I whipped up (sorry if it is terse), and it covers things you already discussed with Mark. I also like Mark's <cfloop> examples above (below). Lol...Where ever this response ends up.

So we have:

• query recordcount (max)
• starting in your range
• ending in your range
• output per page

With bonus pageNum querystring for your next grouping of records (which I think is something you would like).

Then it can look like this in your page:

<cfparam name="pageNum" default="1">

<cfquery name="q" datasource="#application.dsn#">
    select * from yourTable 
</cfquery>

<cfset maxRows = 10>
<cfset startRow = min( ( pageNum-1 ) * maxRows+1, max( q.recordCount,1 ) )>
<cfset endRow = min( startRow + maxRows-1, q.recordCount )>
<cfset totalPages = ceiling( q.recordCount/maxRows )>

<cfset loopercount = round( q.recordCount/10 )>

<cfoutput>
    <cfloop from="1" to="#looperCount#" index="i">
            <a href="?pageNum=#i#">#i#</a>
    </cfloop>
</cfoutput> 

<br><br>

<cfoutput
    query="q" 
    startrow="#startRow#"
    maxrows="#maxRows#">

    #id#<br>

</cfoutput>

回答2:

You need to show how you are actually navigating in your code - that's where the secret sauce is buried. You have everything else you need (maybe more than you need).

You probably have a cfoutput or cfloop in your code somewhere. You would use your startrow and displayrows to output a set number of rows from the records - like so:

<Cfoutput query="records" startrow="#next#" maxrows="#displayrows#">

... code to output your data goes here

</cfoutput>

If you are using cfloop it is similar.

<Cfloop query="records" startrow="#next#" endrow="#next+displayrows#">

...code to output your data. 

</cfloop>

You can also use an index loop like so:

<cfloop from="#next#" to="#next+displayrows#" index="x">

.... your outputs will look like this: 
#records[columname][x]#

</cfoutput>

HOpefully one of those samples will ring a bell. The logic you put in your code snippets is only creating a starting point and defining how many loops. It's the output that teases out the records to display.

Also note the comment - you almost never need evaluate() in your code.

回答3:

I worked this out using a cfform tag with BACK - MORE - HOME submit buttons.

The first page had the query for ID 1 to 25 and a MORE submit button. hidden field was the count 25

The next page had HOME and MORE buttons Home had a hidden field of 1 More had a hidden field of count + 25 (50)

The next page had BACK HOME and MORE buttons Back had hidden field of count - 25 HOME had a hidden field of 1 MORE had a hidden field of count + 25 (75)

and so on.

Query used the number of the hidden field depending on the value of the SUBMIT button to create the query WHERE and output the 25 rows

 <cfif submit IS "NEXT">

   <cfset count1 = #count# + 1>
   <cfset count2 = #count# + 25>

 <cfelseif submit is "BACK">

   <cfset count1 = #count# - 26>
   <cfset count2 = #count#>

 <cfelseif submit is "HOME">

   <cfset count1 = 1>
   <cfset count2 = 25>

 </cfif>

In query

 SELECT *
 FROM mytabl
 WHERE ID BETWEEN #count1# AND #count2#

The display

 <table>
   <cfoutput query="myquery">
     <tr>
       <td>
         #my data1#
       </td>
       <td>
         #my data2#
       </td>
    </cfoutput>
     </tr>
  <table>