list of records via custom controller

Question

I'm using following simple code to get list of Account via custom controller but it is not returning records.what I'm doing wrong ?

<apex:page controller="listcontroller" >
<apex:Form >
<apex:pagemessages ></apex:pagemessages>
   <apex:pageblock >
     <apex:pageblockTable value="{!acclist}" var="a">
        <apex:column >
         <apex:inputField value=" {!a.name}" />
       </apex:column>

     </apex:pageblockTable>
    </apex:pageblock>
  </apex:Form>
 </apex:page>

my apex code is :

public class listcontroller {
public List<Account> acclist{get;set;}
Public pagereference listcontroller()
{ 
acclist = [select id, name, industry from account limit 10 ];
return null;
}

}

I was reading this example in salesforce help https://www.salesforce.com/docs/developer/pages/Content/pages_custom_list_controller.htm

and it has made use of standardSet Controller, which seems little complex comparing to what I've written . is its(set controller) usage is necessary in case of custom controller to get list of records?

Answer 1

It looks like you were trying to make a constructor method, but by adding a return type and value, it has become a standard controller action. You can either remove the return type and value or make it a proper controller action (and rename it, please). Constructor:

Public listcontroller(){ 
    acclist = [select id, name, industry from account limit 10 ];
}

Or as a controller action:

Public PageReference getAccountList(){ 
    acclist = [select id, name, industry from account limit 10 ];
    return null;
}

Call this using @Prabhat's technique provided in his answer.

An alternative good technique is to explicitly get the list when you need it, in the getter of your account list. Try this:

public List<Account> acclist {
    get {
        if (acclist = null) {
            acclist = [select id, name, industry from account limit 10 ];
        }
        return acclist;
    }
    private set;
}

This is an example of a lazy accessor - meaning that when the apex:pageblockTable need the list, it calls the getter, ensuring that it will always have data in the list.

Answer 2

The reason its not returning any thing because you have used query in page reference and You need to invoke page reference method in your vf page.

Use action parameter in your apex:page tag something like this.

<apex:page controller="listcontroller"  action = {!listcontroller}>