I'm having a field of picklist say field1 and a field NetAmount in page1....In page2 Whenever i change the value of picklist corresponding NetAmount Should display...

My page and class

  Field1
    <apex:outputPanel styleClass="requiredInput" layout="block"   >
      <apex:outputPanel styleClass="requiredBlock" layout="block"/>
        <apex:selectlist value="{!Selectin}" size="1" >
          <apex:selectoptions value="{!selectname}" />
          </apex:selectlist>
        </apex:outputpanel>   
      <apex:outputlabel value="Payment Terms"/>
    <apex:outputtext value="{!payment.Net__c}"/>

    public object__c payment{get;set;}

    string Selectin;
    Public string getSelectin(){return Selectin;}
    public void setSelectin(string selectin){this.selectin = Selectin;}
    public list<selectoption> getselectname()
    {
      list<selectoption> option = new list<selectoption>();         
      for(object__c invoice : [select id,name from object__c limit 10] )         
          option.add(new selectoption(invoice.name,invoice.name));
      return option;     
    } 
    public const(){
       payment = [select Net__c from object__c limit 1];
    }

Attribution to: eagerinsf

Possible Suggestion/Solution #1

There's a few ways to do this, but the way I'd handle it is to have an actionsupport on the selectlist that invokes an action method to update the payment.Net__c field. Something along the lines of:

  <apex:selectlist value="{!Selectin}" size="1" >
     <apex:selectoptions value="{!selectname}" />
     <apex:actionSupport event="onchange" action="{!updateNet}" rerender="net"/>
  </apex:selectlist>
  <apex:outputPanel id="net">
     <apex:outputlabel value="Payment Terms"/>
     <apex:outputtext value="{!payment.Net__c}"/>
  </apex:outputPanel

and then in the controller:

public void updateNet()
{
   List<Net__c> nets=[select Net__c from Object__c where name=:selectIn];
   if (nets.size()>0)
   {
      payment.Net__c=nets[0].Net__c;
   }
}

This assumes that the net__c record can be retrieved via the selected name 'selectIn'- if not, you'll need to adjust this to carry out the appropriate selection/calculation.

Attribution to: Bob Buzzard
This content is remixed from stackoverflow or stackexchange. Please visit https://salesforce.stackexchange.com/questions/3603